// SPDX-License-Identifier: GPL-2.0
/* xfrm_iptfs: IPTFS encapsulation support
*
* April 21 2022, Christian Hopps <chopps@labn.net>
*
* Copyright (c) 2022, LabN Consulting, L.L.C.
*
*/
#include <linux/kernel.h>
#include <linux/icmpv6.h>
#include <linux/skbuff_ref.h>
#include <net/gro.h>
#include <net/icmp.h>
#include <net/ip6_route.h>
#include <net/inet_ecn.h>
#include <net/xfrm.h>
#include <crypto/aead.h>
#include "xfrm_inout.h"
#include "trace_iptfs.h"
/* IPTFS encap (header) values. */
#define IPTFS_SUBTYPE_BASIC 0
#define IPTFS_SUBTYPE_CC 1
/* ----------------------------------------------- */
/* IP-TFS default SA values (tunnel egress/dir-in) */
/* ----------------------------------------------- */
/**
* define IPTFS_DEFAULT_DROP_TIME_USECS - default drop time
*
* The default IPTFS drop time in microseconds. The drop time is the amount of
* time before a missing out-of-order IPTFS tunnel packet is considered lost.
* See also the reorder window.
*
* Default 1s.
*/
#define IPTFS_DEFAULT_DROP_TIME_USECS 1000000
/**
* define IPTFS_DEFAULT_REORDER_WINDOW - default reorder window size
*
* The default IPTFS reorder window size. The reorder window size dictates the
* maximum number of IPTFS tunnel packets in a sequence that may arrive out of
* order.
*
* Default 3. (tcp folks suggested)
*/
#define IPTFS_DEFAULT_REORDER_WINDOW 3
/* ------------------------------------------------ */
/* IPTFS default SA values (tunnel ingress/dir-out) */
/* ------------------------------------------------ */
/**
* define IPTFS_DEFAULT_INIT_DELAY_USECS - default initial output delay
*
* The initial output delay is the amount of time prior to servicing the output
* queue after queueing the first packet on said queue. This applies anytime the
* output queue was previously empty.
*
* Default 0.
*/
#define IPTFS_DEFAULT_INIT_DELAY_USECS 0
/**
* define IPTFS_DEFAULT_MAX_QUEUE_SIZE - default max output queue size.
*
* The default IPTFS max output queue size in octets. The output queue is where
* received packets destined for output over an IPTFS tunnel are stored prior to
* being output in aggregated/fragmented form over the IPTFS tunnel.
*
* Default 1M.
*/
#define IPTFS_DEFAULT_MAX_QUEUE_SIZE (1024 * 10240)
/* Assumed: skb->head is cache aligned.
*
* L2 Header resv: Arrange for cacheline to start at skb->data - 16 to keep the
* to-be-pushed L2 header in the same cacheline as resulting `skb->data` (i.e.,
* the L3 header). If cacheline size is > 64 then skb->data + pushed L2 will all
* be in a single cacheline if we simply reserve 64 bytes.
*
* L3 Header resv: For L3+L2 headers (i.e., skb->data points at the IPTFS payload)
* we want `skb->data` to be cacheline aligned and all pushed L2L3 headers will
* be in their own cacheline[s]. 128 works for cachelins up to 128 bytes, for
* any larger cacheline sizes the pushed headers will simply share the cacheline
* with the start of the IPTFS payload (skb->data).
*/
#define XFRM_IPTFS_MIN_L3HEADROOM 128
#define XFRM_IPTFS_MIN_L2HEADROOM (L1_CACHE_BYTES > 64 ? 64 : 64 + 16)
/* Min to try to share outer iptfs skb data vs copying into new skb */
#define IPTFS_PKT_SHARE_MIN 129
#define NSECS_IN_USEC 1000
#define IPTFS_HRTIMER_MODE HRTIMER_MODE_REL_SOFT
/**
* struct xfrm_iptfs_config - configuration for the IPTFS tunnel.
* @pkt_size: size of the outer IP packet. 0 to use interface and MTU discovery,
* otherwise the user specified value.
* @max_queue_size: The maximum number of octets allowed to be queued to be sent
* over the IPTFS SA. The queue size is measured as the size of all the
* packets enqueued.
* @reorder_win_size: the number slots in the reorder window, thus the number of
* packets that may arrive out of order.
* @dont_frag: true to inhibit fragmenting across IPTFS outer packets.
*/
struct xfrm_iptfs_config {
u32 pkt_size; /* outer_packet_size or 0 */
u32 max_queue_size; /* octets */
u16 reorder_win_size;
u8 dont_frag : 1;
};
struct skb_wseq {
struct sk_buff *skb;
u64 drop_time;
};
/**
* struct xfrm_iptfs_data - mode specific xfrm state.
* @cfg: IPTFS tunnel config.
* @x: owning SA (xfrm_state).
* @queue: queued user packets to send.
* @queue_size: number of octets on queue (sum of packet sizes).
* @ecn_queue_size: octets above with ECN mark.
* @init_delay_ns: nanoseconds to wait to send initial IPTFS packet.
* @iptfs_timer: output timer.
* @iptfs_settime: time the output timer was set.
* @payload_mtu: max payload size.
* @w_seq_set: true after first seq received.
* @w_wantseq: waiting for this seq number as next to process (in order).
* @w_saved: the saved buf array (reorder window).
* @w_savedlen: the saved len (not size).
* @drop_lock: lock to protect reorder queue.
* @drop_timer: timer for considering next packet lost.
* @drop_time_ns: timer intervan in nanoseconds.
* @ra_newskb: new pkt being reassembled.
* @ra_wantseq: expected next sequence for reassembly.
* @ra_runt: last pkt bytes from very end of last skb.
* @ra_runtlen: size of ra_runt.
*/
struct xfrm_iptfs_data {
struct xfrm_iptfs_config cfg;
/* Ingress User Input */
struct xfrm_state *x; /* owning state */
struct sk_buff_head queue; /* output queue */
u32 queue_size; /* octets */
u32 ecn_queue_size; /* octets above which ECN mark */
u64 init_delay_ns; /* nanoseconds */
struct hrtimer iptfs_timer; /* output timer */
time64_t iptfs_settime; /* time timer was set */
u32 payload_mtu; /* max payload size */
/* Tunnel input reordering */
bool w_seq_set; /* true after first seq received */
u64 w_wantseq; /* expected next sequence */
struct skb_wseq *w_saved; /* the saved buf array */
u32 w_savedlen; /* the saved len (not size) */
spinlock_t drop_lock;
struct hrtimer drop_timer;
u64 drop_time_ns;
/* Tunnel input reassembly */
struct sk_buff *ra_newskb; /* new pkt being reassembled */
u64 ra_wantseq; /* expected next sequence */
u8 ra_runt[6]; /* last pkt bytes from last skb */
u8 ra_runtlen; /* count of ra_runt */
};
static u32 __iptfs_get_inner_mtu(struct xfrm_state *x, int outer_mtu);
static enum hrtimer_restart iptfs_delay_timer(struct hrtimer *me);
static enum hrtimer_restart iptfs_drop_timer(struct hrtimer *me);
/* ================= */
/* Utility Functions */
/* ================= */
#ifdef TRACEPOINTS_ENABLED
static u32 __trace_ip_proto(struct iphdr *iph)
{
if (iph->version == 4)
return iph->protocol;
return ((struct ipv6hdr *)iph)->nexthdr;
}
static u32 __trace_ip_proto_seq(struct iphdr *iph)
{
void *nexthdr;
u32 protocol = 0;
if (iph->version == 4) {
nexthdr = (void *)(iph + 1);
protocol = iph->protocol;
} else if (iph->version == 6) {
nexthdr = (void *)(((struct ipv6hdr *)(iph)) + 1);
protocol = ((struct ipv6hdr *)(iph))->nexthdr;
}
switch (protocol) {
case IPPROTO_ICMP:
return ntohs(((struct icmphdr *)nexthdr)->un.echo.sequence);
case IPPROTO_ICMPV6:
return ntohs(((struct icmp6hdr *)nexthdr)->icmp6_sequence);
case IPPROTO_TCP:
return ntohl(((struct tcphdr *)nexthdr)->seq);
case IPPROTO_UDP:
return ntohs(((struct udphdr *)nexthdr)->source);
default:
return 0;
}
}
#endif /*TRACEPOINTS_ENABLED*/
static u64 __esp_seq(struct sk_buff *skb)
{
u64 seq = ntohl(XFRM_SKB_CB(skb)->seq.input.low);
return seq | (u64)ntohl(XFRM_SKB_CB(skb)->seq.input.hi) << 32;
}
/* ======================= */
/* IPTFS SK_BUFF Functions */
/* ======================= */
/**
* iptfs_alloc_skb() - Allocate a new `skb`.
* @tpl: the skb to copy required meta-data from.
* @len: the linear length of the head data, zero is fine.
* @l3resv: true if skb reserve needs to support pushing L3 headers
*
* A new `skb` is allocated and required meta-data is copied from `tpl`, the
* head data is sized to `len` + reserved space set according to the @l3resv
* boolean.
*
* When @l3resv is false, resv is XFRM_IPTFS_MIN_L2HEADROOM which arranges for
* `skb->data - 16` which is a good guess for good cache alignment (placing the
* to be pushed L2 header at the start of a cacheline.
*
* Otherwise, @l3resv is true and resv is set to the correct reserved space for
* dst->dev plus the calculated L3 overhead for the xfrm dst or
* XFRM_IPTFS_MIN_L3HEADROOM whichever is larger. This is then cache aligned so
* that all the headers will commonly fall in a cacheline when possible.
*
* l3resv=true is used on tunnel ingress (tx), because we need to reserve for
* the new IPTFS packet (i.e., L2+L3 headers). On tunnel egress (rx) the data
* being copied into the skb includes the user L3 headers already so we only
* need to reserve for L2.
*
* Return: the new skb or NULL.
*/
static struct sk_buff *iptfs_alloc_skb(struct sk_buff *tpl, u32 len, bool l3resv)
{
struct sk_buff *skb;
u32 resv;
if (!l3resv) {
resv = XFRM_IPTFS_MIN_L2HEADROOM;
} else {
struct dst_entry *dst = skb_dst(tpl);
resv = LL_RESERVED_SPACE(dst->dev) + dst->header_len;
resv = max(resv, XFRM_IPTFS_MIN_L3HEADROOM);
resv = L1_CACHE_ALIGN(resv);
}
skb = alloc_skb(len + resv, GFP_ATOMIC | __GFP_NOWARN);
if (!skb)
return NULL;
skb_reserve(skb, resv);
if (!l3resv) {
/* xfrm_input resume needs dev and xfrm ext from tunnel pkt */
skb->dev = tpl->dev;
__skb_ext_copy(skb, tpl);
}
/* dropped by xfrm_input, used by xfrm_output */
skb_dst_copy(skb, tpl);
return skb;
}
/**
* iptfs_skb_head_to_frag() - initialize a skb_frag_t based on skb head data
* @skb: skb with the head data
* @frag: frag to initialize
*/
static void iptfs_skb_head_to_frag(const struct sk_buff *skb, skb_frag_t *frag)
{
struct page *page = virt_to_head_page(skb->data);
unsigned char *addr = (unsigned char *)page_address(page);
skb_frag_fill_page_desc(frag, page, skb->data - addr, skb_headlen(skb));
}
/**
* struct iptfs_skb_frag_walk - use to track a walk through fragments
* @fragi: current fragment index
* @past: length of data in fragments before @fragi
* @total: length of data in all fragments
* @nr_frags: number of fragments present in array
* @initial_offset: the value passed in to skb_prepare_frag_walk()
* @frags: the page fragments inc. room for head page
* @pp_recycle: copy of skb->pp_recycle
*/
struct iptfs_skb_frag_walk {
u32 fragi;
u32 past;
u32 total;
u32 nr_frags;
u32 initial_offset;
skb_frag_t frags[MAX_SKB_FRAGS + 1];
bool pp_recycle;
};
/**
* iptfs_skb_prepare_frag_walk() - initialize a frag walk over an skb.
* @skb: the skb to walk.
* @initial_offset: start the walk @initial_offset into the skb.
* @walk: the walk to initialize
*
* Future calls to skb_add_frags() will expect the @offset value to be at
* least @initial_offset large.
*/
static void iptfs_skb_prepare_frag_walk(struct sk_buff *skb, u32 initial_offset,
struct iptfs_skb_frag_walk *walk)
{
struct skb_shared_info *shinfo = skb_shinfo(skb);
skb_frag_t *frag, *from;
u32 i;
walk->initial_offset = initial_offset;
walk->fragi = 0;
walk->past = 0;
walk->total = 0;
walk->nr_frags = 0;
walk->pp_recycle = skb->pp_recycle;
if (skb->head_frag) {
if (initial_offset >= skb_headlen(skb)) {
initial_offset -= skb_headlen(skb);
} else {
frag = &walk->frags[walk->nr_frags++];
iptfs_skb_head_to_frag(skb, frag);
frag->offset += initial_offset;
frag->len -= initial_offset;
walk->total += frag->len;
initial_offset = 0;
}
} else {
initial_offset -= skb_headlen(skb);
}
for (i = 0; i < shinfo->nr_frags; i++) {
from = &shinfo->frags[i];
if (initial_offset >= from->len) {
initial_offset -= from->len;
continue;
}
frag = &walk->frags[walk->nr_frags++];
*frag = *from;
if (initial_offset) {
frag->offset += initial_offset;
frag->len -= initial_offset;
initial_offset = 0;
}
walk->total += frag->len;
}
}
static u32 iptfs_skb_reset_frag_walk(struct iptfs_skb_frag_walk *walk,
u32 offset)
{
/* Adjust offset to refer to internal walk values */
offset -= walk->initial_offset;
/* Get to the correct fragment for offset */
while (offset < walk->past) {
walk->past -= walk->frags[--walk->fragi].len;
if (offset >= walk->past)
break;
}
while (offset >= walk->past + walk->frags[walk->fragi].len)
walk->past += walk->frags[walk->fragi++].len;
/* offset now relative to this current frag */
offset -= walk->past;
return offset;
}
/**
* iptfs_skb_can_add_frags() - check if ok to add frags from walk to skb
* @skb: skb to check for adding frags to
* @walk: the walk that will be used as source for frags.
* @offset: offset from beginning of original skb to start from.
* @len: amount of data to add frag references to in @skb.
*
* Return: true if ok to add frags.
*/
static bool iptfs_skb_can_add_frags(const struct sk_buff *skb,
struct iptfs_skb_frag_walk *walk,
u32 offset, u32 len)
{
struct skb_shared_info *shinfo = skb_shinfo(skb);
u32 fragi, nr_frags, fraglen;
if (skb_has_frag_list(skb) || skb->pp_recycle != walk->pp_recycle)
return false;
/* Make offset relative to current frag after setting that */
offset = iptfs_skb_reset_frag_walk(walk, offset);
/* Verify we have array space for the fragments we need to add */
fragi = walk->fragi;
nr_frags = shinfo->nr_frags;
while (len && fragi < walk->nr_frags) {
skb_frag_t *frag = &walk->frags[fragi];
fraglen = frag->len;
if (offset) {
fraglen -= offset;
offset = 0;
}
if (++nr_frags > MAX_SKB_FRAGS)
return false;
if (len <= fraglen)
return true;
len -= fraglen;
fragi++;
}
/* We may not copy all @len but what we have will fit. */
return true;
}
/**
* iptfs_skb_add_frags() - add a range of fragment references into an skb
* @skb: skb to add references into
* @walk: the walk to add referenced fragments from.
* @offset: offset from beginning of original skb to start from.
* @len: amount of data to add frag references to in @skb.
*
* iptfs_skb_can_add_frags() should be called before this function to verify
* that the destination @skb is compatible with the walk and has space in the
* array for the to be added frag references.
*
* Return: The number of bytes not added to @skb b/c we reached the end of the
* walk before adding all of @len.
*/
static int iptfs_skb_add_frags(struct sk_buff *skb,
struct iptfs_skb_frag_walk *walk, u32 offset,
u32 len)
{
struct skb_shared_info *shinfo = skb_shinfo(skb);
u32 fraglen;
if (!walk->nr_frags || offset >= walk->total + walk->initial_offset)
return len;
/* make offset relative to current frag after setting that */
offset = iptfs_skb_reset_frag_walk(walk, offset);
while (len && walk->fragi < walk->nr_frags) {
skb_frag_t *frag = &walk->frags[walk->fragi];
skb_frag_t *tofrag = &shinfo->frags[shinfo->nr_frags];
*tofrag = *frag;
if (offset) {
tofrag->offset += offset;
tofrag->len -= offset;
offset = 0;
}
__skb_frag_ref(tofrag);
shinfo->nr_frags++;
shinfo->flags |= SKBFL_SHARED_FRAG;
/* see if we are done */
fraglen = tofrag->len;
if (len < fraglen) {
tofrag->len = len;
skb->len += len;
skb->data_len += len;
return 0;
}
/* advance to next source fragment */
len -= fraglen; /* careful, use dst bv_len */
skb->len += fraglen; /* careful, " " " */
skb->data_len += fraglen; /* careful, " " " */
walk->past += frag->len; /* careful, use src bv_len */
walk->fragi++;
}
return len;
}
/* ================================== */
/* IPTFS Trace Event Definitions */
/* ================================== */
#define CREATE_TRACE_POINTS
#include "trace_iptfs.h"
/* ================================== */
/* IPTFS Receiving (egress) Functions */
/* ================================== */
/**
* iptfs_pskb_add_frags() - Create and add frags into a new sk_buff.
* @tpl: template to create new skb from.
* @walk: The source for fragments to add.
* @off: The offset into @walk to add frags from, also used with @st and
* @copy_len.
* @len: The length of data to add covering frags from @walk into @skb.
* This must be <= @skblen.
* @st: The sequence state to copy from into the new head skb.
* @copy_len: Copy @copy_len bytes from @st at offset @off into the new skb
* linear space.
*
* Create a new sk_buff `skb` using the template @tpl. Copy @copy_len bytes from
* @st into the new skb linear space, and then add shared fragments from the
* frag walk for the remaining @len of data (i.e., @len - @copy_len bytes).
*
* Return: The newly allocated sk_buff `skb` or NULL if an error occurs.
*/
static struct sk_buff *
iptfs_pskb_add_frags(struct sk_buff *tpl, struct iptfs_skb_frag_walk *walk,
u32 off, u32 len, struct skb_seq_state *st, u32 copy_len)
{
struct sk_buff *skb;
skb = iptfs_alloc_skb(tpl, copy_len, false);
if (!skb)
return NULL;
/* this should not normally be happening */
if (!iptfs_skb_can_add_frags(skb, walk, off + copy_len,
len - copy_len)) {
kfree_skb(skb);
return NULL;
}
if (copy_len &&
skb_copy_seq_read(st, off, skb_put(skb, copy_len), copy_len)) {
XFRM_INC_STATS(dev_net(st->root_skb->dev),
LINUX_MIB_XFRMINERROR);
kfree_skb(skb);
return NULL;
}
iptfs_skb_add_frags(skb, walk, off + copy_len, len - copy_len);
return skb;
}
/**
* iptfs_pskb_extract_seq() - Create and load data into a new sk_buff.
* @skblen: the total data size for `skb`.
* @st: The source for the rest of the data to copy into `skb`.
* @off: The offset into @st to copy data from.
* @len: The length of data to copy from @st into `skb`. This must be <=
* @skblen.
*
* Create a new sk_buff `skb` with @skblen of packet data space. If non-zero,
* copy @rlen bytes of @runt into `skb`. Then using seq functions copy @len
* bytes from @st into `skb` starting from @off.
*
* It is an error for @len to be greater than the amount of data left in @st.
*
* Return: The newly allocated sk_buff `skb` or NULL if an error occurs.
*/
static struct sk_buff *
iptfs_pskb_extract_seq(u32 skblen, struct skb_seq_state *st, u32 off, int len)
{
struct sk_buff *skb = iptfs_alloc_skb(st->root_skb, skblen, false);
if (!skb)
return NULL;
if (skb_copy_seq_read(st, off, skb_put(skb, len), len)) {
XFRM_INC_STATS(dev_net(st->root_skb->dev), LINUX_MIB_XFRMINERROR);
kfree_skb(skb);
return NULL;
}
return skb;
}
/**
* iptfs_input_save_runt() - save data in xtfs runt space.
* @xtfs: xtfs state
* @seq: the current sequence
* @buf: packet data
* @len: length of packet data
*
* Save the small (`len`) start of a fragmented packet in `buf` in the xtfs data
* runt space.
*/
static void iptfs_input_save_runt(struct xfrm_iptfs_data *xtfs, u64 seq,
u8 *buf, int len)
{
memcpy(xtfs->ra_runt, buf, len);
xtfs->ra_runtlen = len;
xtfs->ra_wantseq = seq + 1;
}
/**
* __iptfs_iphlen() - return the v4/v6 header length using packet data.
* @data: pointer at octet with version nibble
*
* The version data has been checked to be valid (i.e., either 4 or 6).
*
* Return: the IP header size based on the IP version.
*/
static u32 __iptfs_iphlen(u8 *data)
{
struct iphdr *iph = (struct iphdr *)data;
if (iph->version == 0x4)
return sizeof(*iph);
return sizeof(struct ipv6hdr);
}
/**
* __iptfs_iplen() - return the v4/v6 length using packet data.
* @data: pointer to ip (v4/v6) packet header
*
* Grab the IPv4 or IPv6 length value in the start of the inner packet header
* pointed to by `data`. Assumes data len is enough for the length field only.
*
* The version data has been checked to be valid (i.e., either 4 or 6).
*
* Return: the length value.
*/
static u32 __iptfs_iplen(u8 *data)
{
struct iphdr *iph = (struct iphdr *)data;
if (iph->version == 0x4)
return ntohs(iph->tot_len);
return ntohs(((struct ipv6hdr *)iph)->payload_len) +
sizeof(struct ipv6hdr);
}
/**
* iptfs_complete_inner_skb() - finish preparing the inner packet for gro recv.
* @x: xfrm state
* @skb: the inner packet
*
* Finish the standard xfrm processing on the inner packet prior to sending back
* through gro_cells_receive. We do this separately b/c we are building a list
* of packets in the hopes that one day a list will be taken by
* xfrm_input.
*/
static void iptfs_complete_inner_skb(struct xfrm_state *x, struct sk_buff *skb)
{
skb_reset_network_header(skb);
/* The packet is going back through gro_cells_receive no need to
* set this.
*/
skb_reset_transport_header(skb);
/* Packet already has checksum value set. */
skb->ip_summed = CHECKSUM_NONE;
/* Our skb will contain the header data copied when this outer packet
* which contained the start of this inner packet. This is true
* when we allocate a new skb as well as when we reuse the existing skb.
*/
if (ip_hdr(skb)->version == 0x4) {
struct iphdr *iph = ip_hdr(skb);
if (x->props.flags & XFRM_STATE_DECAP_DSCP)
ipv4_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, iph);
if (!(x->props.flags & XFRM_STATE_NOECN))
if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
IP_ECN_set_ce(iph);
skb->protocol = htons(ETH_P_IP);
} else {
struct ipv6hdr *iph = ipv6_hdr(skb);
if (x->props.flags & XFRM_STATE_DECAP_DSCP)
ipv6_copy_dscp(XFRM_MODE_SKB_CB(skb)->tos, iph);
if (!(x->props.flags & XFRM_STATE_NOECN))
if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
IP6_ECN_set_ce(skb, iph);
skb->protocol = htons(ETH_P_IPV6);
}
}
static void __iptfs_reassem_done(struct xfrm_iptfs_data *xtfs, bool free)
{
assert_spin_locked(&xtfs->drop_lock);
/* We don't care if it works locking takes care of things */
hrtimer_try_to_cancel(&xtfs->drop_timer);
if (free)
kfree_skb(xtfs->ra_newskb);
xtfs->ra_newskb = NULL;
}
/**
* iptfs_reassem_abort() - In-progress packet is aborted free the state.
* @xtfs: xtfs state
*/
static void iptfs_reassem_abort(struct xfrm_iptfs_data *xtfs)
{
__iptfs_reassem_done(xtfs, true);
}
/**
* iptfs_reassem_done() - In-progress packet is complete, clear the state.
* @xtfs: xtfs state
*/
static void iptfs_reassem_done(struct xfrm_iptfs_data *xtfs)
{
__iptfs_reassem_done(xtfs, false);
}
/**
* iptfs_reassem_cont() - Continue the reassembly of an inner packets.
* @xtfs: xtfs state
* @seq: sequence of current packet
* @st: seq read stat for current packet
* @skb: current packet
* @data: offset into sequential packet data
* @blkoff: packet blkoff value
* @list: list of skbs to enqueue completed packet on
*
* Process an IPTFS payload that has a non-zero `blkoff` or when we are
* expecting the continuation b/c we have a runt or in-progress packet.
*
* Return: the new data offset to continue processing from.
*/
static u32 iptfs_reassem_cont(struct xfrm_iptfs_data *xtfs, u64 seq,
struct skb_seq_state *st, struct sk_buff *skb,
u32 data, u32 blkoff, struct list_head *list)
{
struct iptfs_skb_frag_walk _fragwalk;
struct iptfs_skb_frag_walk *fragwalk = NULL;
struct sk_buff *newskb = xtfs->ra_newskb;
u32 remaining = skb->len - data;
u32 runtlen = xtfs->ra_runtlen;
u32 copylen, fraglen, ipremain, iphlen, iphremain, rrem;
/* Handle packet fragment we aren't expecting */
if (!runtlen && !xtfs->ra_newskb)
return data + min(blkoff, remaining);
/* Important to remember that input to this function is an ordered
* packet stream (unless the user disabled the reorder window). Thus if
* we are waiting for, and expecting the next packet so we can continue
* assembly, a newer sequence number indicates older ones are not coming
* (or if they do should be ignored). Technically we can receive older
* ones when the reorder window is disabled; however, the user should
* have disabled fragmentation in this case, and regardless we don't
* deal with it.
*
* blkoff could be zero if the stream is messed up (or it's an all pad
* insertion) be careful to handle that case in each of the below
*/
/* Too old case: This can happen when the reorder window is disabled so
* ordering isn't actually guaranteed.
*/
if (seq < xtfs->ra_wantseq)
return data + remaining;
/* Too new case: We missed what we wanted cleanup. */
if (seq > xtfs->ra_wantseq) {
XFRM_INC_STATS(xs_net(xtfs->x), LINUX_MIB_XFRMINIPTFSERROR);
goto abandon;
}
if (blkoff == 0) {
if ((*skb->data & 0xF0) != 0) {
XFRM_INC_STATS(xs_net(xtfs->x),
LINUX_MIB_XFRMINIPTFSERROR);
goto abandon;
}
/* Handle all pad case, advance expected sequence number.
* (RFC 9347 S2.2.3)
*/
xtfs->ra_wantseq++;
/* will end parsing */
return data + remaining;
}
if (runtlen) {
/* Regardless of what happens we're done with the runt */
xtfs->ra_runtlen = 0;
/* The start of this inner packet was at the very end of the last
* iptfs payload which didn't include enough for the ip header
* length field. We must have *at least* that now.
*/
rrem = sizeof(xtfs->ra_runt) - runtlen;
if (remaining < rrem || blkoff < rrem) {
XFRM_INC_STATS(xs_net(xtfs->x),
LINUX_MIB_XFRMINIPTFSERROR);
goto abandon;
}
/* fill in the runt data */
if (skb_copy_seq_read(st, data, &xtfs->ra_runt[runtlen],
rrem)) {
XFRM_INC_STATS(xs_net(xtfs->x),
LINUX_MIB_XFRMINBUFFERERROR);
goto abandon;
}
/* We have enough data to get the ip length value now,
* allocate an in progress skb
*/
ipremain = __iptfs_iplen(xtfs->ra_runt);
if (ipremain < sizeof(xtfs->ra_runt)) {
/* length has to be at least runtsize large */
XFRM_INC_STATS(xs_net(xtfs->x),
LINUX_MIB_XFRMINIPTFSERROR);
goto abandon;
}
/* For the runt case we don't attempt sharing currently. NOTE:
* Currently, this IPTFS implementation will not create runts.
*/
newskb = iptfs_alloc_skb(skb, ipremain, false);
if (!newskb) {
XFRM_INC_STATS(xs_net(xtfs->x), LINUX_MIB_XFRMINERROR);
goto abandon;
}
xtfs->ra_newskb = newskb;
/* Copy the runt data into the buffer, but leave data
* pointers the same as normal non-runt case. The extra `rrem`
* recopied bytes are basically cacheline free. Allows using
* same logic below to complete.
*/
memcpy(skb_put(newskb, runtlen), xtfs->ra_runt,
sizeof(xtfs->ra_runt));
}
/* Continue reassembling the packet */
ipremain = __iptfs_iplen(newskb->data);
iphlen = __iptfs_iphlen(newskb->data);
ipremain -= newskb->len;
if (blkoff < ipremain) {
/* Corrupt data, we don't have enough to complete the packet */
XFRM_INC_STATS(xs_net(xtfs->x), LINUX_MIB_XFRMINIPTFSERROR);
goto abandon;
}
/* We want the IP header in linear space */
if (newskb->len < iphlen) {
iphremain = iphlen - newskb->len;
if (blkoff < iphremain) {
XFRM_INC_STATS(xs_net(xtfs->x),
LINUX_MIB_XFRMINIPTFSERROR);
goto abandon;
}
fraglen = min(blkoff, remaining);
copylen = min(fraglen, iphremain);
if (skb_copy_seq_read(st, data, skb_put(newskb, copylen),
copylen)) {
XFRM_INC_STATS(xs_net(xtfs->x),
LINUX_MIB_XFRMINBUFFERERROR);
goto abandon;
}
/* this is a silly condition that might occur anyway */
if (copylen < iphremain) {
xtfs->ra_wantseq++;
return data + fraglen;
}
/* update data and things derived from it */
data += copylen;
blkoff -= copylen;
remaining -= copylen;
ipremain -= copylen;
}
fraglen = min(blkoff, remaining);
copylen = min(fraglen, ipremain);
/* If we may have the opportunity to share prepare a fragwalk. */
if (!skb_has_frag_list(skb) && !skb_has_frag_list(newskb) &&
(skb->head_frag || skb->len == skb->data_len) &&
skb->pp_recycle == newskb->pp_recycle) {
fragwalk = &_fragwalk;
iptfs_skb_prepare_frag_walk(skb, data, fragwalk);
}
/* Try share then copy. */
if (fragwalk &&
iptfs_skb_can_add_frags(newskb, fragwalk, data, copylen)) {
iptfs_skb_add_frags(newskb, fragwalk, data, copylen);
} else {
if (skb_linearize(newskb)) {
XFRM_INC_STATS(xs_net(xtfs->x),
LINUX_MIB_XFRMINBUFFERERROR);
goto abandon;
}
/* copy fragment data into newskb */
if (skb_copy_seq_read(st, data, skb_put(newskb, copylen),
copylen)) {
XFRM_INC_STATS(xs_net(xtfs->x),
LINUX_MIB_XFRMINBUFFERERROR);
goto abandon;
}
}
if (copylen < ipremain) {
xtfs->ra_wantseq++;
} else {
/* We are done with packet reassembly! */
iptfs_reassem_done(xtfs);
iptfs_complete_inner_skb(xtfs->x, newskb);
list_add_tail(&newskb->list, list);
}
/* will continue on to new data block or end */
return data + fraglen;
abandon:
if (xtfs->ra_newskb) {
iptfs_reassem_abort(xtfs);
} else {
xtfs->ra_runtlen = 0;
xtfs->ra_wantseq = 0;
}
/* skip past fragment, maybe to end */
return data + min(blkoff, remaining);
}
static bool __input_process_payload(struct xfrm_state *x, u32 data,
struct skb_seq_state *skbseq,
struct list_head *sublist)
{
u8 hbytes[sizeof(struct ipv6hdr)];
struct iptfs_skb_frag_walk _fragwalk;
struct iptfs_skb_frag_walk *fragwalk = NULL;
struct sk_buff *defer, *first_skb, *next, *skb;
const unsigned char *old_mac;
struct xfrm_iptfs_data *xtfs;
struct iphdr *iph;
struct net *net;
u32 first_iplen, iphlen, iplen, remaining, tail;
u32 capturelen;
u64 seq;
bool first_skb_partial = false;
xtfs = x->mode_data;
net = xs_net(x);
skb = skbseq->root_skb;
first_skb = NULL;
defer = NULL;
seq = __esp_seq(skb);
/* Save the old mac header if set */
old_mac = skb_mac_header_was_set(skb) ? skb_mac_header(skb) : NULL;
/* New packets */
tail = skb->len;
while (data < tail) {
__be16 protocol = 0;
/* Gather information on the next data block.
* `data` points to the start of the data block.
*/
remaining = tail - data;
/* try and copy enough bytes to read length from ipv4/ipv6 */
iphlen = min_t(u32, remaining, 6);
if (skb_copy_seq_read(skbseq, data, hbytes, iphlen)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
goto done;
}
iph = (struct iphdr *)hbytes;
if (iph->version == 0x4) {
/* must have at least tot_len field present */
if (remaining < 4) {
/* save the bytes we have, advance data and exit */
iptfs_input_save_runt(xtfs, seq, hbytes,
remaining);
data += remaining;
break;
}
iplen = be16_to_cpu(iph->tot_len);
iphlen = iph->ihl << 2;
if (iplen < iphlen || iphlen < sizeof(*iph)) {
XFRM_INC_STATS(net,
LINUX_MIB_XFRMINHDRERROR);
goto done;
}
protocol = cpu_to_be16(ETH_P_IP);
XFRM_MODE_SKB_CB(skbseq->root_skb)->tos = iph->tos;
} else if (iph->version == 0x6) {
/* must have at least payload_len field present */
if (remaining < 6) {
/* save the bytes we have, advance data and exit */
iptfs_input_save_runt(xtfs, seq, hbytes,
remaining);
data += remaining;
break;
}
iplen = be16_to_cpu(((struct ipv6hdr *)hbytes)->payload_len);
iplen += sizeof(struct ipv6hdr);
iphlen = sizeof(struct ipv6hdr);
protocol = cpu_to_be16(ETH_P_IPV6);
XFRM_MODE_SKB_CB(skbseq->root_skb)->tos =
ipv6_get_dsfield((struct ipv6hdr *)iph);
} else if (iph->version == 0x0) {
/* pad */
data = tail;
break;
} else {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
goto done;
}
if (unlikely(skbseq->stepped_offset)) {
/* We need to reset our seq read, it can't backup at
* this point.
*/
struct sk_buff *save = skbseq->root_skb;
skb_abort_seq_read(skbseq);
skb_prepare_seq_read(save, data, tail, skbseq);
}
if (first_skb) {
skb = NULL;
} else {
first_skb = skb;
first_iplen = iplen;
fragwalk = NULL;
/* We are going to skip over `data` bytes to reach the
* start of the IP header of `iphlen` len for `iplen`
* inner packet.
*/
if (skb_has_frag_list(skb)) {
defer = skb;
skb = NULL;
} else if (data + iphlen <= skb_headlen(skb) &&
/* make sure our header is 32-bit aligned? */
/* ((uintptr_t)(skb->data + data) & 0x3) == 0 && */
skb_tailroom(skb) + tail - data >= iplen) {
/* Reuse the received skb.
*
* We have enough headlen to pull past any
* initial fragment data, leaving at least the
* IP header in the linear buffer space.
*
* For linear buffer space we only require that
* linear buffer space is large enough to
* eventually hold the entire reassembled
* packet (by including tailroom in the check).
*
* For non-linear tailroom is 0 and so we only
* re-use if the entire packet is present
* already.
*
* NOTE: there are many more options for
* sharing, KISS for now. Also, this can produce
* skb's with the IP header unaligned to 32
* bits. If that ends up being a problem then a
* check should be added to the conditional
* above that the header lies on a 32-bit
* boundary as well.
*/
skb_pull(skb, data);
/* our range just changed */
data = 0;
tail = skb->len;
remaining = skb->len;
skb->protocol = protocol;
skb_mac_header_rebuild(skb);
if (skb->mac_len)
eth_hdr(skb)->h_proto = skb->protocol;
/* all pointers could be changed now reset walk */
skb_abort_seq_read(skbseq);
skb_prepare_seq_read(skb, data, tail, skbseq);
} else if (skb->head_frag &&
/* We have the IP header right now */
remaining >= iphlen) {
fragwalk = &_fragwalk;
iptfs_skb_prepare_frag_walk(skb, data, fragwalk);
defer = skb;
skb = NULL;
} else {
/* We couldn't reuse the input skb so allocate a
* new one.
*/
defer = skb;
skb = NULL;
}
/* Don't trim `first_skb` until the end as we are
* walking that data now.
*/
}
capturelen = min(iplen, remaining);
if (!skb) {
if (!fragwalk ||
/* Large enough to be worth sharing */
iplen < IPTFS_PKT_SHARE_MIN ||
/* Have IP header + some data to share. */
capturelen <= iphlen ||
/* Try creating skb and adding frags */
!(skb = iptfs_pskb_add_frags(first_skb, fragwalk,
data, capturelen,
skbseq, iphlen))) {
skb = iptfs_pskb_extract_seq(iplen, skbseq, data, capturelen);
}
if (!skb) {
/* skip to next packet or done */
data += capturelen;
continue;
}
skb->protocol = protocol;
if (old_mac) {
/* rebuild the mac header */
skb_set_mac_header(skb, -first_skb->mac_len);
memcpy(skb_mac_header(skb), old_mac, first_skb->mac_len);
eth_hdr(skb)->h_proto = skb->protocol;
}
}
data += capturelen;
if (skb->len < iplen) {
/* Start reassembly */
spin_lock(&xtfs->drop_lock);
xtfs->ra_newskb = skb;
xtfs->ra_wantseq = seq + 1;
if (!hrtimer_is_queued(&xtfs->drop_timer)) {
/* softirq blocked lest the timer fire and interrupt us */
hrtimer_start(&xtfs->drop_timer,
xtfs->drop_time_ns,
IPTFS_HRTIMER_MODE);
}
spin_unlock(&xtfs->drop_lock);
first_skb_partial = (first_skb == skb);
break;
}
iptfs_complete_inner_skb(x, skb);
list_add_tail(&skb->list, sublist);
}
if (data != tail)
/* this should not happen from the above code */
XFRM_INC_STATS(net, LINUX_MIB_XFRMINIPTFSERROR);
if (first_skb && first_iplen && !defer && !first_skb_partial) {
/* first_skb is queued b/c !defer and not partial */
if (pskb_trim(first_skb, first_iplen)) {
/* error trimming */
list_del(&first_skb->list);
defer = first_skb;
}
first_skb->ip_summed = CHECKSUM_NONE;
}
/* Send the packets! */
list_for_each_entry_safe(skb, next, sublist, list) {
skb_list_del_init(skb);
if (xfrm_input(skb, 0, 0, -2))
kfree_skb(skb);
}
done:
skb = skbseq->root_skb;
skb_abort_seq_read(skbseq);
if (defer) {
consume_skb(defer);
} else if (!first_skb) {
/* skb is the original passed in skb, but we didn't get far
* enough to process it as the first_skb, if we had it would
* either be save in ra_newskb, trimmed and sent on as an skb or
* placed in defer to be freed.
*/
kfree_skb(skb);
}
return true;
}
/**
* iptfs_input_ordered() - handle next in order IPTFS payload.
* @x: xfrm state
* @skb: current packet
*
* Process the IPTFS payload in `skb` and consume it afterwards.
*/
static void iptfs_input_ordered(struct xfrm_state *x, struct sk_buff *skb)
{
struct ip_iptfs_cc_hdr iptcch;
struct skb_seq_state skbseq;
struct list_head sublist; /* rename this it's just a list */
struct xfrm_iptfs_data *xtfs;
struct ip_iptfs_hdr *ipth;
struct net *net;
u32 blkoff, data, remaining;
bool consumed = false;
u64 seq;
xtfs = x->mode_data;
net = xs_net(x);
seq = __esp_seq(skb);
/* Large enough to hold both types of header */
ipth = (struct ip_iptfs_hdr *)&iptcch;
skb_prepare_seq_read(skb, 0, skb->len, &skbseq);
/* Get the IPTFS header and validate it */
if (skb_copy_seq_read(&skbseq, 0, ipth, sizeof(*ipth))) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
goto done;
}
data = sizeof(*ipth);
trace_iptfs_egress_recv(skb, xtfs, be16_to_cpu(ipth->block_offset));
/* Set data past the basic header */
if (ipth->subtype == IPTFS_SUBTYPE_CC) {
/* Copy the rest of the CC header */
remaining = sizeof(iptcch) - sizeof(*ipth);
if (skb_copy_seq_read(&skbseq, data, ipth + 1, remaining)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINBUFFERERROR);
goto done;
}
data += remaining;
} else if (ipth->subtype != IPTFS_SUBTYPE_BASIC) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
goto done;
}
if (ipth->flags != 0) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMINHDRERROR);
goto done;
}
INIT_LIST_HEAD(&sublist);
/* Handle fragment at start of payload, and/or waiting reassembly. */
blkoff = ntohs(ipth->block_offset);
/* check before locking i.e., maybe */
if (blkoff || xtfs->ra_runtlen || xtfs->ra_newskb) {
spin_lock(&xtfs->drop_lock);
/* check again after lock */
if (blkoff || xtfs->ra_runtlen || xtfs->ra_newskb) {
data = iptfs_reassem_cont(xtfs, seq, &skbseq, skb, data,
blkoff, &sublist);
}
spin_unlock(&xtfs->drop_lock);
}
/* New packets */
consumed = __input_process_payload(x, data, &skbseq, &sublist);
done:
if (!consumed) {
skb = skbseq.root_skb;
skb_abort_seq_read(&skbseq);
kfree_skb(skb);
}
}
/* ------------------------------- */
/* Input (Egress) Re-ordering Code */
/* ------------------------------- */
static void __vec_shift(struct xfrm_iptfs_data *xtfs, u32 shift)
{
u32 savedlen = xtfs->w_savedlen;
if (shift > savedlen)
shift = savedlen;
if (shift != savedlen)
memcpy(xtfs->w_saved, xtfs->w_saved + shift,
(savedlen - shift) * sizeof(*xtfs->w_saved));
memset(xtfs->w_saved + savedlen - shift, 0,
shift * sizeof(*xtfs->w_saved));
xtfs->w_savedlen -= shift;
}
static void __reorder_past(struct xfrm_iptfs_data *xtfs, struct sk_buff *inskb,
struct list_head *freelist)
{
list_add_tail(&inskb->list, freelist);
}
static u32 __reorder_drop(struct xfrm_iptfs_data *xtfs, struct list_head *list)
{
struct skb_wseq *s, *se;
const u32 savedlen = xtfs->w_savedlen;
time64_t now = ktime_get_raw_fast_ns();
u32 count = 0;
u32 scount = 0;
if (xtfs->w_saved[0].drop_time > now)
goto set_timer;
++xtfs->w_wantseq;
/* Keep flushing packets until we reach a drop time greater than now. */
s = xtfs->w_saved;
se = s + savedlen;
do {
/* Walking past empty slots until we reach a packet */
for (; s < se && !s->skb; s++) {
if (s->drop_time > now)
goto outerdone;
}
/* Sending packets until we hit another empty slot. */
for (; s < se && s->skb; scount++, s++)
list_add_tail(&s->skb->list, list);
} while (s < se);
outerdone:
count = s - xtfs->w_saved;
if (count) {
xtfs->w_wantseq += count;
/* Shift handled slots plus final empty slot into slot 0. */
__vec_shift(xtfs, count);
}
if (xtfs->w_savedlen) {
set_timer:
/* Drifting is OK */
hrtimer_start(&xtfs->drop_timer,
xtfs->w_saved[0].drop_time - now,
IPTFS_HRTIMER_MODE);
}
return scount;
}
static void __reorder_this(struct xfrm_iptfs_data *xtfs, struct sk_buff *inskb,
struct list_head *list)
{
struct skb_wseq *s, *se;
const u32 savedlen = xtfs->w_savedlen;
u32 count = 0;
/* Got what we wanted. */
list_add_tail(&inskb->list, list);
++xtfs->w_wantseq;
if (!savedlen)
return;
/* Flush remaining consecutive packets. */
/* Keep sending until we hit another missed pkt. */
for (s = xtfs->w_saved, se = s + savedlen; s < se && s->skb; s++)
list_add_tail(&s->skb->list, list);
count = s - xtfs->w_saved;
if (count)
xtfs->w_wantseq += count;
/* Shift handled slots plus final empty slot into slot 0. */
__vec_shift(xtfs, count + 1);
}
/* Set the slot's drop time and all the empty slots below it until reaching a
* filled slot which will already be set.
*/
static void iptfs_set_window_drop_times(struct xfrm_iptfs_data *xtfs, int index)
{
const u32 savedlen = xtfs->w_savedlen;
struct skb_wseq *s = xtfs->w_saved;
time64_t drop_time;
assert_spin_locked(&xtfs->drop_lock);
if (savedlen > index + 1) {
/* we are below another, our drop time and the timer are already set */
return;
}
/* we are the most future so get a new drop time. */
drop_time = ktime_get_raw_fast_ns();
drop_time += xtfs->drop_time_ns;
/* Walk back through the array setting drop times as we go */
s[index].drop_time = drop_time;
while (index-- > 0 && !s[index].skb)
s[index].drop_time = drop_time;
/* If we walked all the way back, schedule the drop timer if needed */
if (index == -1 && !hrtimer_is_queued(&xtfs->drop_timer))
hrtimer_start(&xtfs->drop_timer, xtfs->drop_time_ns,
IPTFS_HRTIMER_MODE);
}
static void __reorder_future_fits(struct xfrm_iptfs_data *xtfs,
struct sk_buff *inskb,
struct list_head *freelist)
{
const u64 inseq = __esp_seq(inskb);
const u64 wantseq = xtfs->w_wantseq;
const u64 distance = inseq - wantseq;
const u32 savedlen = xtfs->w_savedlen;
const u32 index = distance - 1;
/* Handle future sequence number received which fits in the window.
*
* We know we don't have the seq we want so we won't be able to flush
* anything.
*/
/* slot count is 4, saved size is 3 savedlen is 2
*
* "window boundary" is based on the fixed window size
* distance is also slot number
* index is an array index (i.e., - 1 of slot)
* : : - implicit NULL after array len
*
* +--------- used length (savedlen == 2)
* | +----- array size (nslots - 1 == 3)
* | | + window boundary (nslots == 4)
* V V | V
* |
* 0 1 2 3 | slot number
* --- 0 1 2 | array index
* [-] [b] : :| array
*
* "2" "3" "4" *5*| seq numbers
*
* We receive seq number 5
* distance == 3 [inseq(5) - w_wantseq(2)]
* index == 2 [distance(6) - 1]
*/
if (xtfs->w_saved[index].skb) {
/* a dup of a future */
list_add_tail(&inskb->list, freelist);
return;
}
xtfs->w_saved[index].skb = inskb;
xtfs->w_savedlen = max(savedlen, index + 1);
iptfs_set_window_drop_times(xtfs, index);
}
static void __reorder_future_shifts(struct xfrm_iptfs_data *xtfs,
struct sk_buff *inskb,
struct list_head *list)
{
const u32 nslots = xtfs->cfg.reorder_win_size + 1;
const u64 inseq = __esp_seq(inskb);
u32 savedlen = xtfs->w_savedlen;
u64 wantseq = xtfs->w_wantseq;
struct skb_wseq *wnext;
struct sk_buff *slot0;
u32 beyond, shifting, slot;
u64 distance;
/* Handle future sequence number received.
*
* IMPORTANT: we are at least advancing w_wantseq (i.e., wantseq) by 1
* b/c we are beyond the window boundary.
*
* We know we don't have the wantseq so that counts as a drop.
*/
/* example: slot count is 4, array size is 3 savedlen is 2, slot 0 is
* the missing sequence number.
*
* the final slot at savedlen (index savedlen - 1) is always occupied.
*
* beyond is "beyond array size" not savedlen.
*
* +--------- array length (savedlen == 2)
* | +----- array size (nslots - 1 == 3)
* | | +- window boundary (nslots == 4)
* V V |
* |
* 0 1 2 3 | slot number
* --- 0 1 2 | array index
* [b] [c] : :| array
* |
* "2" "3" "4" "5"|*6* seq numbers
*
* We receive seq number 6
* distance == 4 [inseq(6) - w_wantseq(2)]
* newslot == distance
* index == 3 [distance(4) - 1]
* beyond == 1 [newslot(4) - lastslot((nslots(4) - 1))]
* shifting == 1 [min(savedlen(2), beyond(1)]
* slot0_skb == [b], and should match w_wantseq
*
* +--- window boundary (nslots == 4)
* 0 1 2 3 | 4 slot number
* --- 0 1 2 | 3 array index
* [b] : : : :| array
* "2" "3" "4" "5" *6* seq numbers
*
* We receive seq number 6
* distance == 4 [inseq(6) - w_wantseq(2)]
* newslot == distance
* index == 3 [distance(4) - 1]
* beyond == 1 [newslot(4) - lastslot((nslots(4) - 1))]
* shifting == 1 [min(savedlen(1), beyond(1)]
* slot0_skb == [b] and should match w_wantseq
*
* +-- window boundary (nslots == 4)
* 0 1 2 3 | 4 5 6 slot number
* --- 0 1 2 | 3 4 5 array index
* [-] [c] : :| array
* "2" "3" "4" "5" "6" "7" *8* seq numbers
*
* savedlen = 2, beyond = 3
* iter 1: slot0 == NULL, missed++, lastdrop = 2 (2+1-1), slot0 = [-]
* iter 2: slot0 == NULL, missed++, lastdrop = 3 (2+2-1), slot0 = [c]
* 2 < 3, extra = 1 (3-2), missed += extra, lastdrop = 4 (2+2+1-1)
*
* We receive seq number 8
* distance == 6 [inseq(8) - w_wantseq(2)]
* newslot == distance
* index == 5 [distance(6) - 1]
* beyond == 3 [newslot(6) - lastslot((nslots(4) - 1))]
* shifting == 2 [min(savedlen(2), beyond(3)]
*
* slot0_skb == NULL changed from [b] when "savedlen < beyond" is true.
*/
/* Now send any packets that are being shifted out of saved, and account
* for missing packets that are exiting the window as we shift it.
*/
distance = inseq - wantseq;
beyond = distance - (nslots - 1);
/* If savedlen > beyond we are shifting some, else all. */
shifting = min(savedlen, beyond);
/* slot0 is the buf that just shifted out and into slot0 */
slot0 = NULL;
wnext = xtfs->w_saved;
for (slot = 1; slot <= shifting; slot++, wnext++) {
/* handle what was in slot0 before we occupy it */
if (slot0)
list_add_tail(&slot0->list, list);
slot0 = wnext->skb;
wnext->skb = NULL;
}
/* slot0 is now either NULL (in which case it's what we now are waiting
* for, or a buf in which case we need to handle it like we received it;
* however, we may be advancing past that buffer as well..
*/
/* Handle case where we need to shift more than we had saved, slot0 will
* be NULL iff savedlen is 0, otherwise slot0 will always be
* non-NULL b/c we shifted the final element, which is always set if
* there is any saved, into slot0.
*/
if (savedlen < beyond) {
if (savedlen != 0)
list_add_tail(&slot0->list, list);
slot0 = NULL;
/* slot0 has had an empty slot pushed into it */
}
/* Remove the entries */
__vec_shift(xtfs, beyond);
/* Advance want seq */
xtfs->w_wantseq += beyond;
/* Process drops here when implementing congestion control */
/* We've shifted. plug the packet in at the end. */
xtfs->w_savedlen = nslots - 1;
xtfs->w_saved[xtfs->w_savedlen - 1].skb = inskb;
iptfs_set_window_drop_times(xtfs, xtfs->w_savedlen - 1);
/* if we don't have a slot0 then we must wait for it */
if (!slot0)
return;
/* If slot0, seq must match new want seq */
/* slot0 is valid, treat like we received expected. */
__reorder_this(xtfs, slot0, list);
}
/* Receive a new packet into the reorder window. Return a list of ordered
* packets from the window.
*/
static void iptfs_input_reorder(struct xfrm_iptfs_data *xtfs,
struct sk_buff *inskb, struct list_head *list,
struct list_head *freelist)
{
const u32 nslots = xtfs->cfg.reorder_win_size + 1;
u64 inseq = __esp_seq(inskb);
u64 wantseq;
assert_spin_locked(&xtfs->drop_lock);
if (unlikely(!xtfs->w_seq_set)) {
xtfs->w_seq_set = true;
xtfs->w_wantseq = inseq;
}
wantseq = xtfs->w_wantseq;
if (likely(inseq == wantseq))
__reorder_this(xtfs, inskb, list);
else if (inseq < wantseq)
__reorder_past(xtfs, inskb, freelist);
else if ((inseq - wantseq) < nslots)
__reorder_future_fits(xtfs, inskb, freelist);
else
__reorder_future_shifts(xtfs, inskb, list);
}
/**
* iptfs_drop_timer() - Handle drop timer expiry.
* @me: the timer
*
* This is similar to our input function.
*
* The drop timer is set when we start an in progress reassembly, and also when
* we save a future packet in the window saved array.
*
* NOTE packets in the save window are always newer WRT drop times as
* they get further in the future. i.e. for:
*
* if slots (S0, S1, ... Sn) and `Dn` is the drop time for slot `Sn`,
* then D(n-1) <= D(n).
*
* So, regardless of why the timer is firing we can always discard any inprogress
* fragment; either it's the reassembly timer, or slot 0 is going to be
* dropped as S0 must have the most recent drop time, and slot 0 holds the
* continuation fragment of the in progress packet.
*
* Returns HRTIMER_NORESTART.
*/
static enum hrtimer_restart iptfs_drop_timer(struct hrtimer *me)
{
struct sk_buff *skb, *next;
struct list_head list;
struct xfrm_iptfs_data *xtfs;
struct xfrm_state *x;
u32 count;
xtfs = container_of(me, typeof(*xtfs), drop_timer);
x = xtfs->x;
INIT_LIST_HEAD(&list);
spin_lock(&xtfs->drop_lock);
/* Drop any in progress packet */
skb = xtfs->ra_newskb;
xtfs->ra_newskb = NULL;
/* Now drop as many packets as we should from the reordering window
* saved array
*/
count = xtfs->w_savedlen ? __reorder_drop(xtfs, &list) : 0;
spin_unlock(&xtfs->drop_lock);
if (skb)
kfree_skb_reason(skb, SKB_DROP_REASON_FRAG_REASM_TIMEOUT);
if (count) {
list_for_each_entry_safe(skb, next, &list, list) {
skb_list_del_init(skb);
iptfs_input_ordered(x, skb);
}
}
return HRTIMER_NORESTART;
}
/**
* iptfs_input() - handle receipt of iptfs payload
* @x: xfrm state
* @skb: the packet
*
* We have an IPTFS payload order it if needed, then process newly in order
* packets.
*
* Return: -EINPROGRESS to inform xfrm_input to stop processing the skb.
*/
static int iptfs_input(struct xfrm_state *x, struct sk_buff *skb)
{
struct list_head freelist, list;
struct xfrm_iptfs_data *xtfs = x->mode_data;
struct sk_buff *next;
/* Fast path for no reorder window. */
if (xtfs->cfg.reorder_win_size == 0) {
iptfs_input_ordered(x, skb);
goto done;
}
/* Fetch list of in-order packets from the reordering window as well as
* a list of buffers we need to now free.
*/
INIT_LIST_HEAD(&list);
INIT_LIST_HEAD(&freelist);
spin_lock(&xtfs->drop_lock);
iptfs_input_reorder(xtfs, skb, &list, &freelist);
spin_unlock(&xtfs->drop_lock);
list_for_each_entry_safe(skb, next, &list, list) {
skb_list_del_init(skb);
iptfs_input_ordered(x, skb);
}
list_for_each_entry_safe(skb, next, &freelist, list) {
skb_list_del_init(skb);
kfree_skb(skb);
}
done:
/* We always have dealt with the input SKB, either we are re-using it,
* or we have freed it. Return EINPROGRESS so that xfrm_input stops
* processing it.
*/
return -EINPROGRESS;
}
/* ================================= */
/* IPTFS Sending (ingress) Functions */
/* ================================= */
/* ------------------------- */
/* Enqueue to send functions */
/* ------------------------- */
/**
* iptfs_enqueue() - enqueue packet if ok to send.
* @xtfs: xtfs state
* @skb: the packet
*
* Return: true if packet enqueued.
*/
static bool iptfs_enqueue(struct xfrm_iptfs_data *xtfs, struct sk_buff *skb)
{
u64 newsz = xtfs->queue_size + skb->len;
struct iphdr *iph;
assert_spin_locked(&xtfs->x->lock);
if (newsz > xtfs->cfg.max_queue_size)
return false;
/* Set ECN CE if we are above our ECN queue threshold */
if (newsz > xtfs->ecn_queue_size) {
iph = ip_hdr(skb);
if (iph->version == 4)
IP_ECN_set_ce(iph);
else if (iph->version == 6)
IP6_ECN_set_ce(skb, ipv6_hdr(skb));
}
__skb_queue_tail(&xtfs->queue, skb);
xtfs->queue_size += skb->len;
return true;
}
static int iptfs_get_cur_pmtu(struct xfrm_state *x, struct xfrm_iptfs_data *xtfs,
struct sk_buff *skb)
{
struct xfrm_dst *xdst = (struct xfrm_dst *)skb_dst(skb);
u32 payload_mtu = xtfs->payload_mtu;
u32 pmtu = __iptfs_get_inner_mtu(x, xdst->child_mtu_cached);
if (payload_mtu && payload_mtu < pmtu)
pmtu = payload_mtu;
return pmtu;
}
static int iptfs_is_too_big(struct sock *sk, struct sk_buff *skb, u32 pmtu)
{
if (skb->len <= pmtu)
return 0;
/* We only send ICMP too big if the user has configured us as
* dont-fragment.
*/
if (skb->dev)
XFRM_INC_STATS(dev_net(skb->dev), LINUX_MIB_XFRMOUTERROR);
if (sk)
xfrm_local_error(skb, pmtu);
else if (ip_hdr(skb)->version == 4)
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(pmtu));
else
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, pmtu);
return 1;
}
/* IPv4/IPv6 packet ingress to IPTFS tunnel, arrange to send in IPTFS payload
* (i.e., aggregating or fragmenting as appropriate).
* This is set in dst->output for an SA.
*/
static int iptfs_output_collect(struct net *net, struct sock *sk, struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
struct xfrm_state *x = dst->xfrm;
struct xfrm_iptfs_data *xtfs = x->mode_data;
struct sk_buff *segs, *nskb;
u32 pmtu = 0;
bool ok = true;
bool was_gso;
/* We have hooked into dst_entry->output which means we have skipped the
* protocol specific netfilter (see xfrm4_output, xfrm6_output).
* when our timer runs we will end up calling xfrm_output directly on
* the encapsulated traffic.
*
* For both cases this is the NF_INET_POST_ROUTING hook which allows
* changing the skb->dst entry which then may not be xfrm based anymore
* in which case a REROUTED flag is set. and dst_output is called.
*
* For IPv6 we are also skipping fragmentation handling for local
* sockets, which may or may not be good depending on our tunnel DF
* setting. Normally with fragmentation supported we want to skip this
* fragmentation.
*/
if (xtfs->cfg.dont_frag)
pmtu = iptfs_get_cur_pmtu(x, xtfs, skb);
/* Break apart GSO skbs. If the queue is nearing full then we want the
* accounting and queuing to be based on the individual packets not on the
* aggregate GSO buffer.
*/
was_gso = skb_is_gso(skb);
if (!was_gso) {
segs = skb;
} else {
segs = skb_gso_segment(skb, 0);
if (IS_ERR_OR_NULL(segs)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
kfree_skb(skb);
if (IS_ERR(segs))
return PTR_ERR(segs);
return -EINVAL;
}
consume_skb(skb);
skb = NULL;
}
/* We can be running on multiple cores and from the network softirq or
* from user context depending on where the packet is coming from.
*/
spin_lock_bh(&x->lock);
skb_list_walk_safe(segs, skb, nskb) {
skb_mark_not_on_list(skb);
/* Once we drop due to no queue space we continue to drop the
* rest of the packets from that GRO.
*/
if (!ok) {
nospace:
trace_iptfs_no_queue_space(skb, xtfs, pmtu, was_gso);
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTNOQSPACE);
kfree_skb_reason(skb, SKB_DROP_REASON_FULL_RING);
continue;
}
/* If the user indicated no iptfs fragmenting check before
* enqueue.
*/
if (xtfs->cfg.dont_frag && iptfs_is_too_big(sk, skb, pmtu)) {
trace_iptfs_too_big(skb, xtfs, pmtu, was_gso);
kfree_skb_reason(skb, SKB_DROP_REASON_PKT_TOO_BIG);
continue;
}
/* Enqueue to send in tunnel */
ok = iptfs_enqueue(xtfs, skb);
if (!ok)
goto nospace;
trace_iptfs_enqueue(skb, xtfs, pmtu, was_gso);
}
/* Start a delay timer if we don't have one yet */
if (!hrtimer_is_queued(&xtfs->iptfs_timer)) {
hrtimer_start(&xtfs->iptfs_timer, xtfs->init_delay_ns, IPTFS_HRTIMER_MODE);
xtfs->iptfs_settime = ktime_get_raw_fast_ns();
trace_iptfs_timer_start(xtfs, xtfs->init_delay_ns);
}
spin_unlock_bh(&x->lock);
return 0;
}
/* -------------------------- */
/* Dequeue and send functions */
/* -------------------------- */
static void iptfs_output_prepare_skb(struct sk_buff *skb, u32 blkoff)
{
struct ip_iptfs_hdr *h;
size_t hsz = sizeof(*h);
/* now reset values to be pointing at the rest of the packets */
h = skb_push(skb, hsz);
memset(h, 0, hsz);
if (blkoff)
h->block_offset = htons(blkoff);
/* network_header current points at the inner IP packet
* move it to the iptfs header
*/
skb->transport_header = skb->network_header;
skb->network_header -= hsz;
IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
}
/**
* iptfs_copy_create_frag() - create an inner fragment skb.
* @st: The source packet data.
* @offset: offset in @st of the new fragment data.
* @copy_len: the amount of data to copy from @st.
*
* Create a new skb holding a single IPTFS inner packet fragment. @copy_len must
* not be greater than the max fragment size.
*
* Return: the new fragment skb or an ERR_PTR().
*/
static struct sk_buff *iptfs_copy_create_frag(struct skb_seq_state *st, u32 offset, u32 copy_len)
{
struct sk_buff *src = st->root_skb;
struct sk_buff *skb;
int err;
skb = iptfs_alloc_skb(src, copy_len, true);
if (!skb)
return ERR_PTR(-ENOMEM);
/* Now copy `copy_len` data from src */
err = skb_copy_seq_read(st, offset, skb_put(skb, copy_len), copy_len);
if (err) {
kfree_skb(skb);
return ERR_PTR(err);
}
return skb;
}
/**
* iptfs_copy_create_frags() - create and send N-1 fragments of a larger skb.
* @skbp: the source packet skb (IN), skb holding the last fragment in
* the fragment stream (OUT).
* @xtfs: IPTFS SA state.
* @mtu: the max IPTFS fragment size.
*
* This function is responsible for fragmenting a larger inner packet into a
* sequence of IPTFS payload packets. The last fragment is returned rather than
* being sent so that the caller can append more inner packets (aggregation) if
* there is room.
*
* Return: 0 on success or a negative error code on failure
*/
static int iptfs_copy_create_frags(struct sk_buff **skbp, struct xfrm_iptfs_data *xtfs, u32 mtu)
{
struct skb_seq_state skbseq;
struct list_head sublist;
struct sk_buff *skb = *skbp;
struct sk_buff *nskb = *skbp;
u32 copy_len, offset;
u32 to_copy = skb->len - mtu;
u32 blkoff = 0;
int err = 0;
INIT_LIST_HEAD(&sublist);
skb_prepare_seq_read(skb, 0, skb->len, &skbseq);
/* A trimmed `skb` will be sent as the first fragment, later. */
offset = mtu;
to_copy = skb->len - offset;
while (to_copy) {
/* Send all but last fragment to allow agg. append */
trace_iptfs_first_fragmenting(nskb, mtu, to_copy, NULL);
list_add_tail(&nskb->list, &sublist);
/* FUTURE: if the packet has an odd/non-aligning length we could
* send less data in the penultimate fragment so that the last
* fragment then ends on an aligned boundary.
*/
copy_len = min(to_copy, mtu);
nskb = iptfs_copy_create_frag(&skbseq, offset, copy_len);
if (IS_ERR(nskb)) {
XFRM_INC_STATS(xs_net(xtfs->x), LINUX_MIB_XFRMOUTERROR);
skb_abort_seq_read(&skbseq);
err = PTR_ERR(nskb);
nskb = NULL;
break;
}
iptfs_output_prepare_skb(nskb, to_copy);
offset += copy_len;
to_copy -= copy_len;
blkoff = to_copy;
}
skb_abort_seq_read(&skbseq);
/* return last fragment that will be unsent (or NULL) */
*skbp = nskb;
if (nskb)
trace_iptfs_first_final_fragment(nskb, mtu, blkoff, NULL);
/* trim the original skb to MTU */
if (!err)
err = pskb_trim(skb, mtu);
if (err) {
/* Free all frags. Don't bother sending a partial packet we will
* never complete.
*/
kfree_skb(nskb);
list_for_each_entry_safe(skb, nskb, &sublist, list) {
skb_list_del_init(skb);
kfree_skb(skb);
}
return err;
}
/* prepare the initial fragment with an iptfs header */
iptfs_output_prepare_skb(skb, 0);
/* Send all but last fragment, if we fail to send a fragment then free
* the rest -- no point in sending a packet that can't be reassembled.
*/
list_for_each_entry_safe(skb, nskb, &sublist, list) {
skb_list_del_init(skb);
if (!err)
err = xfrm_output(NULL, skb);
else
kfree_skb(skb);
}
if (err)
kfree_skb(*skbp);
return err;
}
/**
* iptfs_first_skb() - handle the first dequeued inner packet for output
* @skbp: the source packet skb (IN), skb holding the last fragment in
* the fragment stream (OUT).
* @xtfs: IPTFS SA state.
* @mtu: the max IPTFS fragment size.
*
* This function is responsible for fragmenting a larger inner packet into a
* sequence of IPTFS payload packets.
*
* The last fragment is returned rather than being sent so that the caller can
* append more inner packets (aggregation) if there is room.
*
* Return: 0 on success or a negative error code on failure
*/
static int iptfs_first_skb(struct sk_buff **skbp, struct xfrm_iptfs_data *xtfs, u32 mtu)
{
struct sk_buff *skb = *skbp;
int err;
/* Classic ESP skips the don't fragment ICMP error if DF is clear on
* the inner packet or ignore_df is set. Otherwise it will send an ICMP
* or local error if the inner packet won't fit it's MTU.
*
* With IPTFS we do not care about the inner packet DF bit. If the
* tunnel is configured to "don't fragment" we error back if things
* don't fit in our max packet size. Otherwise we iptfs-fragment as
* normal.
*/
/* The opportunity for HW offload has ended */
if (skb->ip_summed == CHECKSUM_PARTIAL) {
err = skb_checksum_help(skb);
if (err)
return err;
}
/* We've split gso up before queuing */
trace_iptfs_first_dequeue(skb, mtu, 0, ip_hdr(skb));
/* Consider the buffer Tx'd and no longer owned */
skb_orphan(skb);
/* Simple case -- it fits. `mtu` accounted for all the overhead
* including the basic IPTFS header.
*/
if (skb->len <= mtu) {
iptfs_output_prepare_skb(skb, 0);
return 0;
}
return iptfs_copy_create_frags(skbp, xtfs, mtu);
}
static struct sk_buff **iptfs_rehome_fraglist(struct sk_buff **nextp, struct sk_buff *child)
{
u32 fllen = 0;
/* It might be possible to account for a frag list in addition to page
* fragment if it's a valid state to be in. The page fragments size
* should be kept as data_len so only the frag_list size is removed,
* this must be done above as well.
*/
*nextp = skb_shinfo(child)->frag_list;
while (*nextp) {
fllen += (*nextp)->len;
nextp = &(*nextp)->next;
}
skb_frag_list_init(child);
child->len -= fllen;
child->data_len -= fllen;
return nextp;
}
static void iptfs_consume_frags(struct sk_buff *to, struct sk_buff *from)
{
struct skb_shared_info *fromi = skb_shinfo(from);
struct skb_shared_info *toi = skb_shinfo(to);
unsigned int new_truesize;
/* If we have data in a head page, grab it */
if (!skb_headlen(from)) {
new_truesize = SKB_TRUESIZE(skb_end_offset(from));
} else {
iptfs_skb_head_to_frag(from, &toi->frags[toi->nr_frags]);
skb_frag_ref(to, toi->nr_frags++);
new_truesize = SKB_DATA_ALIGN(sizeof(struct sk_buff));
}
/* Move any other page fragments rather than copy */
memcpy(&toi->frags[toi->nr_frags], fromi->frags,
sizeof(fromi->frags[0]) * fromi->nr_frags);
toi->nr_frags += fromi->nr_frags;
if (fromi->nr_frags)
toi->flags |= fromi->flags & SKBFL_SHARED_FRAG;
fromi->nr_frags = 0;
from->data_len = 0;
from->len = 0;
to->truesize += from->truesize - new_truesize;
from->truesize = new_truesize;
/* We are done with this SKB */
consume_skb(from);
}
static void iptfs_output_queued(struct xfrm_state *x, struct sk_buff_head *list)
{
struct xfrm_iptfs_data *xtfs = x->mode_data;
struct sk_buff *skb, *skb2, **nextp;
struct skb_shared_info *shi, *shi2;
/* If we are fragmenting due to a large inner packet we will output all
* the outer IPTFS packets required to contain the fragments of the
* single large inner packet. These outer packets need to be sent
* consecutively (ESP seq-wise). Since this output function is always
* running from a timer we do not need a lock to provide this guarantee.
* We will output our packets consecutively before the timer is allowed
* to run again on some other CPU.
*/
while ((skb = __skb_dequeue(list))) {
u32 mtu = iptfs_get_cur_pmtu(x, xtfs, skb);
bool share_ok = true;
int remaining;
/* protocol comes to us cleared sometimes */
skb->protocol = x->outer_mode.family == AF_INET ? htons(ETH_P_IP) :
htons(ETH_P_IPV6);
if (skb->len > mtu && xtfs->cfg.dont_frag) {
/* We handle this case before enqueueing so we are only
* here b/c MTU changed after we enqueued before we
* dequeued, just drop these.
*/
XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTERROR);
trace_iptfs_first_toobig(skb, mtu, 0, ip_hdr(skb));
kfree_skb_reason(skb, SKB_DROP_REASON_PKT_TOO_BIG);
continue;
}
/* Convert first inner packet into an outer IPTFS packet,
* dealing with any fragmentation into multiple outer packets
* if necessary.
*/
if (iptfs_first_skb(&skb, xtfs, mtu))
continue;
/* If fragmentation was required the returned skb is the last
* IPTFS fragment in the chain, and it's IPTFS header blkoff has
* been set just past the end of the fragment data.
*
* In either case the space remaining to send more inner packet
* data is `mtu` - (skb->len - sizeof iptfs header). This is b/c
* the `mtu` value has the basic IPTFS header len accounted for,
* and we added that header to the skb so it is a part of
* skb->len, thus we subtract it from the skb length.
*/
remaining = mtu - (skb->len - sizeof(struct ip_iptfs_hdr));
/* Re-home (un-nest) nested fragment lists. We need to do this
* b/c we will simply be appending any following aggregated
* inner packets using the frag list.
*/
shi = skb_shinfo(skb);
nextp = &shi->frag_list;
while (*nextp) {
if (skb_has_frag_list(*nextp))
nextp = iptfs_rehome_fraglist(&(*nextp)->next, *nextp);
else
nextp = &(*nextp)->next;
}
if (shi->frag_list || skb_cloned(skb) || skb_shared(skb))
share_ok = false;
/* See if we have enough space to simply append.
*
* NOTE: Maybe do not append if we will be mis-aligned,
* SW-based endpoints will probably have to copy in this
* case.
*/
while ((skb2 = skb_peek(list))) {
trace_iptfs_ingress_nth_peek(skb2, remaining);
if (skb2->len > remaining)
break;
__skb_unlink(skb2, list);
/* Consider the buffer Tx'd and no longer owned */
skb_orphan(skb);
/* If we don't have a cksum in the packet we need to add
* one before encapsulation.
*/
if (skb2->ip_summed == CHECKSUM_PARTIAL) {
if (skb_checksum_help(skb2)) {
XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTERROR);
kfree_skb(skb2);
continue;
}
}
/* skb->pp_recycle is passed to __skb_flag_unref for all
* frag pages so we can only share pages with skb's who
* match ourselves.
*/
shi2 = skb_shinfo(skb2);
if (share_ok &&
(shi2->frag_list ||
(!skb2->head_frag && skb_headlen(skb)) ||
skb->pp_recycle != skb2->pp_recycle ||
skb_zcopy(skb2) ||
(shi->nr_frags + shi2->nr_frags + 1 > MAX_SKB_FRAGS)))
share_ok = false;
/* Do accounting */
skb->data_len += skb2->len;
skb->len += skb2->len;
remaining -= skb2->len;
trace_iptfs_ingress_nth_add(skb2, share_ok);
if (share_ok) {
iptfs_consume_frags(skb, skb2);
} else {
/* Append to the frag_list */
*nextp = skb2;
nextp = &skb2->next;
if (skb_has_frag_list(skb2))
nextp = iptfs_rehome_fraglist(nextp,
skb2);
skb->truesize += skb2->truesize;
}
}
xfrm_output(NULL, skb);
}
}
static enum hrtimer_restart iptfs_delay_timer(struct hrtimer *me)
{
struct sk_buff_head list;
struct xfrm_iptfs_data *xtfs;
struct xfrm_state *x;
time64_t settime;
xtfs = container_of(me, typeof(*xtfs), iptfs_timer);
x = xtfs->x;
/* Process all the queued packets
*
* softirq execution order: timer > tasklet > hrtimer
*
* Network rx will have run before us giving one last chance to queue
* ingress packets for us to process and transmit.
*/
spin_lock(&x->lock);
__skb_queue_head_init(&list);
skb_queue_splice_init(&xtfs->queue, &list);
xtfs->queue_size = 0;
settime = xtfs->iptfs_settime;
spin_unlock(&x->lock);
/* After the above unlock, packets can begin queuing again, and the
* timer can be set again, from another CPU either in softirq or user
* context (not from this one since we are running at softirq level
* already).
*/
trace_iptfs_timer_expire(xtfs, (unsigned long long)(ktime_get_raw_fast_ns() - settime));
iptfs_output_queued(x, &list);
return HRTIMER_NORESTART;
}
/**
* iptfs_encap_add_ipv4() - add outer encaps
* @x: xfrm state
* @skb: the packet
*
* This was originally taken from xfrm4_tunnel_encap_add. The reason for the
* copy is that IP-TFS/AGGFRAG can have different functionality for how to set
* the TOS/DSCP bits. Sets the protocol to a different value and doesn't do
* anything with inner headers as they aren't pointing into a normal IP
* singleton inner packet.
*
* Return: 0 on success or a negative error code on failure
*/
static int iptfs_encap_add_ipv4(struct xfrm_state *x, struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
struct iphdr *top_iph;
skb_reset_inner_network_header(skb);
skb_reset_inner_transport_header(skb);
skb_set_network_header(skb, -(x->props.header_len - x->props.enc_hdr_len));
skb->mac_header = skb->network_header + offsetof(struct iphdr, protocol);
skb->transport_header = skb->network_header + sizeof(*top_iph);
top_iph = ip_hdr(skb);
top_iph->ihl = 5;
top_iph->version = 4;
top_iph->protocol = IPPROTO_AGGFRAG;
/* As we have 0, fractional, 1 or N inner packets there's no obviously
* correct DSCP mapping to inherit. ECN should be cleared per RFC9347
* 3.1.
*/
top_iph->tos = 0;
top_iph->frag_off = htons(IP_DF);
top_iph->ttl = ip4_dst_hoplimit(xfrm_dst_child(dst));
top_iph->saddr = x->props.saddr.a4;
top_iph->daddr = x->id.daddr.a4;
ip_select_ident(dev_net(dst->dev), skb, NULL);
return 0;
}
#if IS_ENABLED(CONFIG_IPV6)
/**
* iptfs_encap_add_ipv6() - add outer encaps
* @x: xfrm state
* @skb: the packet
*
* This was originally taken from xfrm6_tunnel_encap_add. The reason for the
* copy is that IP-TFS/AGGFRAG can have different functionality for how to set
* the flow label and TOS/DSCP bits. It also sets the protocol to a different
* value and doesn't do anything with inner headers as they aren't pointing into
* a normal IP singleton inner packet.
*
* Return: 0 on success or a negative error code on failure
*/
static int iptfs_encap_add_ipv6(struct xfrm_state *x, struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
struct ipv6hdr *top_iph;
int dsfield;
skb_reset_inner_network_header(skb);
skb_reset_inner_transport_header(skb);
skb_set_network_header(skb, -x->props.header_len + x->props.enc_hdr_len);
skb->mac_header = skb->network_header + offsetof(struct ipv6hdr, nexthdr);
skb->transport_header = skb->network_header + sizeof(*top_iph);
top_iph = ipv6_hdr(skb);
top_iph->version = 6;
top_iph->priority = 0;
memset(top_iph->flow_lbl, 0, sizeof(top_iph->flow_lbl));
top_iph->nexthdr = IPPROTO_AGGFRAG;
/* As we have 0, fractional, 1 or N inner packets there's no obviously
* correct DSCP mapping to inherit. ECN should be cleared per RFC9347
* 3.1.
*/
dsfield = 0;
ipv6_change_dsfield(top_iph, 0, dsfield);
top_iph->hop_limit = ip6_dst_hoplimit(xfrm_dst_child(dst));
top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
return 0;
}
#endif
/**
* iptfs_prepare_output() - prepare the skb for output
* @x: xfrm state
* @skb: the packet
*
* Return: Error value, if 0 then skb values should be as follows:
* - transport_header should point at ESP header
* - network_header should point at Outer IP header
* - mac_header should point at protocol/nexthdr of the outer IP
*/
static int iptfs_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
{
if (x->outer_mode.family == AF_INET)
return iptfs_encap_add_ipv4(x, skb);
if (x->outer_mode.family == AF_INET6) {
#if IS_ENABLED(CONFIG_IPV6)
return iptfs_encap_add_ipv6(x, skb);
#else
return -EAFNOSUPPORT;
#endif
}
return -EOPNOTSUPP;
}
/* ========================== */
/* State Management Functions */
/* ========================== */
/**
* __iptfs_get_inner_mtu() - return inner MTU with no fragmentation.
* @x: xfrm state.
* @outer_mtu: the outer mtu
*
* Return: Correct MTU taking in to account the encap overhead.
*/
static u32 __iptfs_get_inner_mtu(struct xfrm_state *x, int outer_mtu)
{
struct crypto_aead *aead;
u32 blksize;
aead = x->data;
blksize = ALIGN(crypto_aead_blocksize(aead), 4);
return ((outer_mtu - x->props.header_len - crypto_aead_authsize(aead)) &
~(blksize - 1)) - 2;
}
/**
* iptfs_get_inner_mtu() - return the inner MTU for an IPTFS xfrm.
* @x: xfrm state.
* @outer_mtu: Outer MTU for the encapsulated packet.
*
* Return: Correct MTU taking in to account the encap overhead.
*/
static u32 iptfs_get_inner_mtu(struct xfrm_state *x, int outer_mtu)
{
struct xfrm_iptfs_data *xtfs = x->mode_data;
/* If not dont-frag we have no MTU */
if (!xtfs->cfg.dont_frag)
return x->outer_mode.family == AF_INET ? IP_MAX_MTU : IP6_MAX_MTU;
return __iptfs_get_inner_mtu(x, outer_mtu);
}
/**
* iptfs_user_init() - initialize the SA with IPTFS options from netlink.
* @net: the net data
* @x: xfrm state
* @attrs: netlink attributes
* @extack: extack return data
*
* Return: 0 on success or a negative error code on failure
*/
static int iptfs_user_init(struct net *net, struct xfrm_state *x,
struct nlattr **attrs,
struct netlink_ext_ack *extack)
{
struct xfrm_iptfs_data *xtfs = x->mode_data;
struct xfrm_iptfs_config *xc;
u64 q;
xc = &xtfs->cfg;
xc->max_queue_size = IPTFS_DEFAULT_MAX_QUEUE_SIZE;
xc->reorder_win_size = IPTFS_DEFAULT_REORDER_WINDOW;
xtfs->drop_time_ns = IPTFS_DEFAULT_DROP_TIME_USECS * NSECS_IN_USEC;
xtfs->init_delay_ns = IPTFS_DEFAULT_INIT_DELAY_USECS * NSECS_IN_USEC;
if (attrs[XFRMA_IPTFS_DONT_FRAG])
xc->dont_frag = true;
if (attrs[XFRMA_IPTFS_REORDER_WINDOW])
xc->reorder_win_size =
nla_get_u16(attrs[XFRMA_IPTFS_REORDER_WINDOW]);
/* saved array is for saving 1..N seq nums from wantseq */
if (xc->reorder_win_size) {
xtfs->w_saved = kzalloc_objs(*xtfs->w_saved,
xc->reorder_win_size);
if (!xtfs->w_saved) {
NL_SET_ERR_MSG(extack, "Cannot alloc reorder window");
return -ENOMEM;
}
}
if (attrs[XFRMA_IPTFS_PKT_SIZE]) {
xc->pkt_size = nla_get_u32(attrs[XFRMA_IPTFS_PKT_SIZE]);
if (!xc->pkt_size) {
xtfs->payload_mtu = 0;
} else if (xc->pkt_size > x->props.header_len) {
xtfs->payload_mtu = xc->pkt_size - x->props.header_len;
} else {
NL_SET_ERR_MSG(extack,
"Packet size must be 0 or greater than IPTFS/ESP header length");
return -EINVAL;
}
}
if (attrs[XFRMA_IPTFS_MAX_QSIZE])
xc->max_queue_size = nla_get_u32(attrs[XFRMA_IPTFS_MAX_QSIZE]);
if (attrs[XFRMA_IPTFS_DROP_TIME])
xtfs->drop_time_ns =
(u64)nla_get_u32(attrs[XFRMA_IPTFS_DROP_TIME]) *
NSECS_IN_USEC;
if (attrs[XFRMA_IPTFS_INIT_DELAY])
xtfs->init_delay_ns =
(u64)nla_get_u32(attrs[XFRMA_IPTFS_INIT_DELAY]) * NSECS_IN_USEC;
q = (u64)xc->max_queue_size * 95;
do_div(q, 100);
xtfs->ecn_queue_size = (u32)q;
return 0;
}
static unsigned int iptfs_sa_len(const struct xfrm_state *x)
{
struct xfrm_iptfs_data *xtfs = x->mode_data;
struct xfrm_iptfs_config *xc = &xtfs->cfg;
unsigned int l = 0;
if (x->dir == XFRM_SA_DIR_IN) {
l += nla_total_size(sizeof(u32)); /* drop time usec */
l += nla_total_size(sizeof(xc->reorder_win_size));
} else {
if (xc->dont_frag)
l += nla_total_size(0); /* dont-frag flag */
l += nla_total_size(sizeof(u32)); /* init delay usec */
l += nla_total_size(sizeof(xc->max_queue_size));
l += nla_total_size(sizeof(xc->pkt_size));
}
return l;
}
static int iptfs_copy_to_user(struct xfrm_state *x, struct sk_buff *skb)
{
struct xfrm_iptfs_data *xtfs = x->mode_data;
struct xfrm_iptfs_config *xc = &xtfs->cfg;
int ret = 0;
u64 q;
if (x->dir == XFRM_SA_DIR_IN) {
q = xtfs->drop_time_ns;
do_div(q, NSECS_IN_USEC);
ret = nla_put_u32(skb, XFRMA_IPTFS_DROP_TIME, q);
if (ret)
return ret;
ret = nla_put_u16(skb, XFRMA_IPTFS_REORDER_WINDOW,
xc->reorder_win_size);
} else {
if (xc->dont_frag) {
ret = nla_put_flag(skb, XFRMA_IPTFS_DONT_FRAG);
if (ret)
return ret;
}
q = xtfs->init_delay_ns;
do_div(q, NSECS_IN_USEC);
ret = nla_put_u32(skb, XFRMA_IPTFS_INIT_DELAY, q);
if (ret)
return ret;
ret = nla_put_u32(skb, XFRMA_IPTFS_MAX_QSIZE, xc->max_queue_size);
if (ret)
return ret;
ret = nla_put_u32(skb, XFRMA_IPTFS_PKT_SIZE, xc->pkt_size);
}
return ret;
}
static void __iptfs_init_state(struct xfrm_state *x,
struct xfrm_iptfs_data *xtfs)
{
__skb_queue_head_init(&xtfs->queue);
hrtimer_setup(&xtfs->iptfs_timer, iptfs_delay_timer, CLOCK_MONOTONIC, IPTFS_HRTIMER_MODE);
spin_lock_init(&xtfs->drop_lock);
hrtimer_setup(&xtfs->drop_timer, iptfs_drop_timer, CLOCK_MONOTONIC, IPTFS_HRTIMER_MODE);
/* Modify type (esp) adjustment values */
if (x->props.family == AF_INET)
x->props.header_len += sizeof(struct iphdr) + sizeof(struct ip_iptfs_hdr);
else if (x->props.family == AF_INET6)
x->props.header_len += sizeof(struct ipv6hdr) + sizeof(struct ip_iptfs_hdr);
x->props.enc_hdr_len = sizeof(struct ip_iptfs_hdr);
/* Always keep a module reference when x->mode_data is set */
if (x->mode_data != xtfs)
__module_get(x->mode_cbs->owner);
x->mode_data = xtfs;
xtfs->x = x;
}
static int iptfs_clone_state(struct xfrm_state *x, struct xfrm_state *orig)
{
struct skb_wseq *w_saved = NULL;
struct xfrm_iptfs_data *xtfs;
xtfs = kmemdup(orig->mode_data, sizeof(*xtfs), GFP_KERNEL);
if (!xtfs)
return -ENOMEM;
if (xtfs->cfg.reorder_win_size) {
w_saved = kzalloc_objs(*w_saved, xtfs->cfg.reorder_win_size);
if (!w_saved) {
kfree_sensitive(xtfs);
return -ENOMEM;
}
}
xtfs->w_saved = w_saved;
__skb_queue_head_init(&xtfs->queue);
xtfs->queue_size = 0;
hrtimer_setup(&xtfs->iptfs_timer, iptfs_delay_timer, CLOCK_MONOTONIC,
IPTFS_HRTIMER_MODE);
spin_lock_init(&xtfs->drop_lock);
hrtimer_setup(&xtfs->drop_timer, iptfs_drop_timer, CLOCK_MONOTONIC,
IPTFS_HRTIMER_MODE);
xtfs->w_seq_set = false;
xtfs->w_wantseq = 0;
xtfs->w_savedlen = 0;
xtfs->ra_newskb = NULL;
xtfs->ra_wantseq = 0;
xtfs->ra_runtlen = 0;
__module_get(x->mode_cbs->owner);
x->mode_data = xtfs;
xtfs->x = x;
return 0;
}
static int iptfs_init_state(struct xfrm_state *x)
{
struct xfrm_iptfs_data *xtfs;
if (x->mode_data) {
/* We have arrived here from xfrm_state_clone() */
xtfs = x->mode_data;
} else {
xtfs = kzalloc_obj(*xtfs);
if (!xtfs)
return -ENOMEM;
}
__iptfs_init_state(x, xtfs);
return 0;
}
static void iptfs_destroy_state(struct xfrm_state *x)
{
struct xfrm_iptfs_data *xtfs = x->mode_data;
struct sk_buff_head list;
struct skb_wseq *s, *se;
struct sk_buff *skb;
if (!xtfs)
return;
hrtimer_cancel(&xtfs->iptfs_timer);
spin_lock_bh(&xtfs->x->lock);
__skb_queue_head_init(&list);
skb_queue_splice_init(&xtfs->queue, &list);
spin_unlock_bh(&xtfs->x->lock);
while ((skb = __skb_dequeue(&list)))
kfree_skb(skb);
hrtimer_cancel(&xtfs->drop_timer);
if (xtfs->ra_newskb)
kfree_skb(xtfs->ra_newskb);
for (s = xtfs->w_saved, se = s + xtfs->w_savedlen; s < se; s++) {
if (s->skb)
kfree_skb(s->skb);
}
kfree_sensitive(xtfs->w_saved);
kfree_sensitive(xtfs);
module_put(x->mode_cbs->owner);
}
static const struct xfrm_mode_cbs iptfs_mode_cbs = {
.owner = THIS_MODULE,
.init_state = iptfs_init_state,
.clone_state = iptfs_clone_state,
.destroy_state = iptfs_destroy_state,
.user_init = iptfs_user_init,
.copy_to_user = iptfs_copy_to_user,
.sa_len = iptfs_sa_len,
.get_inner_mtu = iptfs_get_inner_mtu,
.input = iptfs_input,
.output = iptfs_output_collect,
.prepare_output = iptfs_prepare_output,
};
static int __init xfrm_iptfs_init(void)
{
int err;
pr_info("xfrm_iptfs: IPsec IP-TFS tunnel mode module\n");
err = xfrm_register_mode_cbs(XFRM_MODE_IPTFS, &iptfs_mode_cbs);
if (err < 0)
pr_info("%s: can't register IP-TFS\n", __func__);
return err;
}
static void __exit xfrm_iptfs_fini(void)
{
xfrm_unregister_mode_cbs(XFRM_MODE_IPTFS);
}
module_init(xfrm_iptfs_init);
module_exit(xfrm_iptfs_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("IP-TFS support for xfrm ipsec tunnels");
