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Diffstat (limited to 'net/ipv4/tcp_ipv4.c')
-rw-r--r--net/ipv4/tcp_ipv4.c326
1 files changed, 284 insertions, 42 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index be23a0b7b89e..75735c9a6a9d 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -352,6 +352,7 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
const int code = icmp_hdr(icmp_skb)->code;
struct sock *sk;
struct sk_buff *skb;
+ struct request_sock *req;
__u32 seq;
__u32 remaining;
int err;
@@ -394,9 +395,12 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
icsk = inet_csk(sk);
tp = tcp_sk(sk);
+ req = tp->fastopen_rsk;
seq = ntohl(th->seq);
if (sk->sk_state != TCP_LISTEN &&
- !between(seq, tp->snd_una, tp->snd_nxt)) {
+ !between(seq, tp->snd_una, tp->snd_nxt) &&
+ (req == NULL || seq != tcp_rsk(req)->snt_isn)) {
+ /* For a Fast Open socket, allow seq to be snt_isn. */
NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
goto out;
}
@@ -435,6 +439,8 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
!icsk->icsk_backoff)
break;
+ /* XXX (TFO) - revisit the following logic for TFO */
+
if (sock_owned_by_user(sk))
break;
@@ -466,6 +472,14 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
goto out;
}
+ /* XXX (TFO) - if it's a TFO socket and has been accepted, rather
+ * than following the TCP_SYN_RECV case and closing the socket,
+ * we ignore the ICMP error and keep trying like a fully established
+ * socket. Is this the right thing to do?
+ */
+ if (req && req->sk == NULL)
+ goto out;
+
switch (sk->sk_state) {
struct request_sock *req, **prev;
case TCP_LISTEN:
@@ -498,7 +512,8 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
case TCP_SYN_SENT:
case TCP_SYN_RECV: /* Cannot happen.
- It can f.e. if SYNs crossed.
+ It can f.e. if SYNs crossed,
+ or Fast Open.
*/
if (!sock_owned_by_user(sk)) {
sk->sk_err = err;
@@ -809,8 +824,12 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)
static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
struct request_sock *req)
{
- tcp_v4_send_ack(skb, tcp_rsk(req)->snt_isn + 1,
- tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd,
+ /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
+ * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
+ */
+ tcp_v4_send_ack(skb, (sk->sk_state == TCP_LISTEN) ?
+ tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt,
+ tcp_rsk(req)->rcv_nxt, req->rcv_wnd,
req->ts_recent,
0,
tcp_md5_do_lookup(sk, (union tcp_md5_addr *)&ip_hdr(skb)->daddr,
@@ -839,7 +858,7 @@ static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
return -1;
- skb = tcp_make_synack(sk, dst, req, rvp);
+ skb = tcp_make_synack(sk, dst, req, rvp, NULL);
if (skb) {
__tcp_v4_send_check(skb, ireq->loc_addr, ireq->rmt_addr);
@@ -849,6 +868,8 @@ static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
ireq->rmt_addr,
ireq->opt);
err = net_xmit_eval(err);
+ if (!tcp_rsk(req)->snt_synack && !err)
+ tcp_rsk(req)->snt_synack = tcp_time_stamp;
}
return err;
@@ -904,8 +925,7 @@ EXPORT_SYMBOL(tcp_syn_flood_action);
/*
* Save and compile IPv4 options into the request_sock if needed.
*/
-static struct ip_options_rcu *tcp_v4_save_options(struct sock *sk,
- struct sk_buff *skb)
+static struct ip_options_rcu *tcp_v4_save_options(struct sk_buff *skb)
{
const struct ip_options *opt = &(IPCB(skb)->opt);
struct ip_options_rcu *dopt = NULL;
@@ -1272,6 +1292,182 @@ static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
};
#endif
+static bool tcp_fastopen_check(struct sock *sk, struct sk_buff *skb,
+ struct request_sock *req,
+ struct tcp_fastopen_cookie *foc,
+ struct tcp_fastopen_cookie *valid_foc)
+{
+ bool skip_cookie = false;
+ struct fastopen_queue *fastopenq;
+
+ if (likely(!fastopen_cookie_present(foc))) {
+ /* See include/net/tcp.h for the meaning of these knobs */
+ if ((sysctl_tcp_fastopen & TFO_SERVER_ALWAYS) ||
+ ((sysctl_tcp_fastopen & TFO_SERVER_COOKIE_NOT_REQD) &&
+ (TCP_SKB_CB(skb)->end_seq != TCP_SKB_CB(skb)->seq + 1)))
+ skip_cookie = true; /* no cookie to validate */
+ else
+ return false;
+ }
+ fastopenq = inet_csk(sk)->icsk_accept_queue.fastopenq;
+ /* A FO option is present; bump the counter. */
+ NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPFASTOPENPASSIVE);
+
+ /* Make sure the listener has enabled fastopen, and we don't
+ * exceed the max # of pending TFO requests allowed before trying
+ * to validating the cookie in order to avoid burning CPU cycles
+ * unnecessarily.
+ *
+ * XXX (TFO) - The implication of checking the max_qlen before
+ * processing a cookie request is that clients can't differentiate
+ * between qlen overflow causing Fast Open to be disabled
+ * temporarily vs a server not supporting Fast Open at all.
+ */
+ if ((sysctl_tcp_fastopen & TFO_SERVER_ENABLE) == 0 ||
+ fastopenq == NULL || fastopenq->max_qlen == 0)
+ return false;
+
+ if (fastopenq->qlen >= fastopenq->max_qlen) {
+ struct request_sock *req1;
+ spin_lock(&fastopenq->lock);
+ req1 = fastopenq->rskq_rst_head;
+ if ((req1 == NULL) || time_after(req1->expires, jiffies)) {
+ spin_unlock(&fastopenq->lock);
+ NET_INC_STATS_BH(sock_net(sk),
+ LINUX_MIB_TCPFASTOPENLISTENOVERFLOW);
+ /* Avoid bumping LINUX_MIB_TCPFASTOPENPASSIVEFAIL*/
+ foc->len = -1;
+ return false;
+ }
+ fastopenq->rskq_rst_head = req1->dl_next;
+ fastopenq->qlen--;
+ spin_unlock(&fastopenq->lock);
+ reqsk_free(req1);
+ }
+ if (skip_cookie) {
+ tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
+ return true;
+ }
+ if (foc->len == TCP_FASTOPEN_COOKIE_SIZE) {
+ if ((sysctl_tcp_fastopen & TFO_SERVER_COOKIE_NOT_CHKED) == 0) {
+ tcp_fastopen_cookie_gen(ip_hdr(skb)->saddr, valid_foc);
+ if ((valid_foc->len != TCP_FASTOPEN_COOKIE_SIZE) ||
+ memcmp(&foc->val[0], &valid_foc->val[0],
+ TCP_FASTOPEN_COOKIE_SIZE) != 0)
+ return false;
+ valid_foc->len = -1;
+ }
+ /* Acknowledge the data received from the peer. */
+ tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
+ return true;
+ } else if (foc->len == 0) { /* Client requesting a cookie */
+ tcp_fastopen_cookie_gen(ip_hdr(skb)->saddr, valid_foc);
+ NET_INC_STATS_BH(sock_net(sk),
+ LINUX_MIB_TCPFASTOPENCOOKIEREQD);
+ } else {
+ /* Client sent a cookie with wrong size. Treat it
+ * the same as invalid and return a valid one.
+ */
+ tcp_fastopen_cookie_gen(ip_hdr(skb)->saddr, valid_foc);
+ }
+ return false;
+}
+
+static int tcp_v4_conn_req_fastopen(struct sock *sk,
+ struct sk_buff *skb,
+ struct sk_buff *skb_synack,
+ struct request_sock *req,
+ struct request_values *rvp)
+{
+ struct tcp_sock *tp = tcp_sk(sk);
+ struct request_sock_queue *queue = &inet_csk(sk)->icsk_accept_queue;
+ const struct inet_request_sock *ireq = inet_rsk(req);
+ struct sock *child;
+ int err;
+
+ req->retrans = 0;
+ req->sk = NULL;
+
+ child = inet_csk(sk)->icsk_af_ops->syn_recv_sock(sk, skb, req, NULL);
+ if (child == NULL) {
+ NET_INC_STATS_BH(sock_net(sk),
+ LINUX_MIB_TCPFASTOPENPASSIVEFAIL);
+ kfree_skb(skb_synack);
+ return -1;
+ }
+ err = ip_build_and_send_pkt(skb_synack, sk, ireq->loc_addr,
+ ireq->rmt_addr, ireq->opt);
+ err = net_xmit_eval(err);
+ if (!err)
+ tcp_rsk(req)->snt_synack = tcp_time_stamp;
+ /* XXX (TFO) - is it ok to ignore error and continue? */
+
+ spin_lock(&queue->fastopenq->lock);
+ queue->fastopenq->qlen++;
+ spin_unlock(&queue->fastopenq->lock);
+
+ /* Initialize the child socket. Have to fix some values to take
+ * into account the child is a Fast Open socket and is created
+ * only out of the bits carried in the SYN packet.
+ */
+ tp = tcp_sk(child);
+
+ tp->fastopen_rsk = req;
+ /* Do a hold on the listner sk so that if the listener is being
+ * closed, the child that has been accepted can live on and still
+ * access listen_lock.
+ */
+ sock_hold(sk);
+ tcp_rsk(req)->listener = sk;
+
+ /* RFC1323: The window in SYN & SYN/ACK segments is never
+ * scaled. So correct it appropriately.
+ */
+ tp->snd_wnd = ntohs(tcp_hdr(skb)->window);
+
+ /* Activate the retrans timer so that SYNACK can be retransmitted.
+ * The request socket is not added to the SYN table of the parent
+ * because it's been added to the accept queue directly.
+ */
+ inet_csk_reset_xmit_timer(child, ICSK_TIME_RETRANS,
+ TCP_TIMEOUT_INIT, TCP_RTO_MAX);
+
+ /* Add the child socket directly into the accept queue */
+ inet_csk_reqsk_queue_add(sk, req, child);
+
+ /* Now finish processing the fastopen child socket. */
+ inet_csk(child)->icsk_af_ops->rebuild_header(child);
+ tcp_init_congestion_control(child);
+ tcp_mtup_init(child);
+ tcp_init_buffer_space(child);
+ tcp_init_metrics(child);
+
+ /* Queue the data carried in the SYN packet. We need to first
+ * bump skb's refcnt because the caller will attempt to free it.
+ *
+ * XXX (TFO) - we honor a zero-payload TFO request for now.
+ * (Any reason not to?)
+ */
+ if (TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq + 1) {
+ /* Don't queue the skb if there is no payload in SYN.
+ * XXX (TFO) - How about SYN+FIN?
+ */
+ tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
+ } else {
+ skb = skb_get(skb);
+ skb_dst_drop(skb);
+ __skb_pull(skb, tcp_hdr(skb)->doff * 4);
+ skb_set_owner_r(skb, child);
+ __skb_queue_tail(&child->sk_receive_queue, skb);
+ tp->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
+ }
+ sk->sk_data_ready(sk, 0);
+ bh_unlock_sock(child);
+ sock_put(child);
+ WARN_ON(req->sk == NULL);
+ return 0;
+}
+
int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
{
struct tcp_extend_values tmp_ext;
@@ -1285,6 +1481,11 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
__be32 daddr = ip_hdr(skb)->daddr;
__u32 isn = TCP_SKB_CB(skb)->when;
bool want_cookie = false;
+ struct flowi4 fl4;
+ struct tcp_fastopen_cookie foc = { .len = -1 };
+ struct tcp_fastopen_cookie valid_foc = { .len = -1 };
+ struct sk_buff *skb_synack;
+ int do_fastopen;
/* Never answer to SYNs send to broadcast or multicast */
if (skb_rtable(skb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
@@ -1319,7 +1520,8 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
tcp_clear_options(&tmp_opt);
tmp_opt.mss_clamp = TCP_MSS_DEFAULT;
tmp_opt.user_mss = tp->rx_opt.user_mss;
- tcp_parse_options(skb, &tmp_opt, &hash_location, 0, NULL);
+ tcp_parse_options(skb, &tmp_opt, &hash_location, 0,
+ want_cookie ? NULL : &foc);
if (tmp_opt.cookie_plus > 0 &&
tmp_opt.saw_tstamp &&
@@ -1365,7 +1567,7 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
ireq->loc_addr = daddr;
ireq->rmt_addr = saddr;
ireq->no_srccheck = inet_sk(sk)->transparent;
- ireq->opt = tcp_v4_save_options(sk, skb);
+ ireq->opt = tcp_v4_save_options(skb);
if (security_inet_conn_request(sk, skb, req))
goto drop_and_free;
@@ -1377,8 +1579,6 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
isn = cookie_v4_init_sequence(sk, skb, &req->mss);
req->cookie_ts = tmp_opt.tstamp_ok;
} else if (!isn) {
- struct flowi4 fl4;
-
/* VJ's idea. We save last timestamp seen
* from the destination in peer table, when entering
* state TIME-WAIT, and check against it before
@@ -1417,16 +1617,54 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
isn = tcp_v4_init_sequence(skb);
}
tcp_rsk(req)->snt_isn = isn;
- tcp_rsk(req)->snt_synack = tcp_time_stamp;
- if (tcp_v4_send_synack(sk, dst, req,
- (struct request_values *)&tmp_ext,
- skb_get_queue_mapping(skb),
- want_cookie) ||
- want_cookie)
+ if (dst == NULL) {
+ dst = inet_csk_route_req(sk, &fl4, req);
+ if (dst == NULL)
+ goto drop_and_free;
+ }
+ do_fastopen = tcp_fastopen_check(sk, skb, req, &foc, &valid_foc);
+
+ /* We don't call tcp_v4_send_synack() directly because we need
+ * to make sure a child socket can be created successfully before
+ * sending back synack!
+ *
+ * XXX (TFO) - Ideally one would simply call tcp_v4_send_synack()
+ * (or better yet, call tcp_send_synack() in the child context
+ * directly, but will have to fix bunch of other code first)
+ * after syn_recv_sock() except one will need to first fix the
+ * latter to remove its dependency on the current implementation
+ * of tcp_v4_send_synack()->tcp_select_initial_window().
+ */
+ skb_synack = tcp_make_synack(sk, dst, req,
+ (struct request_values *)&tmp_ext,
+ fastopen_cookie_present(&valid_foc) ? &valid_foc : NULL);
+
+ if (skb_synack) {
+ __tcp_v4_send_check(skb_synack, ireq->loc_addr, ireq->rmt_addr);
+ skb_set_queue_mapping(skb_synack, skb_get_queue_mapping(skb));
+ } else
+ goto drop_and_free;
+
+ if (likely(!do_fastopen)) {
+ int err;
+ err = ip_build_and_send_pkt(skb_synack, sk, ireq->loc_addr,
+ ireq->rmt_addr, ireq->opt);
+ err = net_xmit_eval(err);
+ if (err || want_cookie)
+ goto drop_and_free;
+
+ tcp_rsk(req)->snt_synack = tcp_time_stamp;
+ tcp_rsk(req)->listener = NULL;
+ /* Add the request_sock to the SYN table */
+ inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
+ if (fastopen_cookie_present(&foc) && foc.len != 0)
+ NET_INC_STATS_BH(sock_net(sk),
+ LINUX_MIB_TCPFASTOPENPASSIVEFAIL);
+ } else if (tcp_v4_conn_req_fastopen(sk, skb, skb_synack, req,
+ (struct request_values *)&tmp_ext))
goto drop_and_free;
- inet_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
return 0;
drop_and_release:
@@ -1500,9 +1738,7 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
newtp->advmss = tcp_sk(sk)->rx_opt.user_mss;
tcp_initialize_rcv_mss(newsk);
- if (tcp_rsk(req)->snt_synack)
- tcp_valid_rtt_meas(newsk,
- tcp_time_stamp - tcp_rsk(req)->snt_synack);
+ tcp_synack_rtt_meas(newsk, req);
newtp->total_retrans = req->retrans;
#ifdef CONFIG_TCP_MD5SIG
@@ -1554,7 +1790,7 @@ static struct sock *tcp_v4_hnd_req(struct sock *sk, struct sk_buff *skb)
struct request_sock *req = inet_csk_search_req(sk, &prev, th->source,
iph->saddr, iph->daddr);
if (req)
- return tcp_check_req(sk, skb, req, prev);
+ return tcp_check_req(sk, skb, req, prev, false);
nsk = inet_lookup_established(sock_net(sk), &tcp_hashinfo, iph->saddr,
th->source, iph->daddr, th->dest, inet_iif(skb));
@@ -1963,20 +2199,13 @@ void tcp_v4_destroy_sock(struct sock *sk)
if (inet_csk(sk)->icsk_bind_hash)
inet_put_port(sk);
- /*
- * If sendmsg cached page exists, toss it.
- */
- if (sk->sk_sndmsg_page) {
- __free_page(sk->sk_sndmsg_page);
- sk->sk_sndmsg_page = NULL;
- }
-
/* TCP Cookie Transactions */
if (tp->cookie_values != NULL) {
kref_put(&tp->cookie_values->kref,
tcp_cookie_values_release);
tp->cookie_values = NULL;
}
+ BUG_ON(tp->fastopen_rsk != NULL);
/* If socket is aborted during connect operation */
tcp_free_fastopen_req(tp);
@@ -2396,7 +2625,7 @@ static void get_openreq4(const struct sock *sk, const struct request_sock *req,
struct seq_file *f, int i, kuid_t uid, int *len)
{
const struct inet_request_sock *ireq = inet_rsk(req);
- int ttd = req->expires - jiffies;
+ long delta = req->expires - jiffies;
seq_printf(f, "%4d: %08X:%04X %08X:%04X"
" %02X %08X:%08X %02X:%08lX %08X %5d %8d %u %d %pK%n",
@@ -2408,7 +2637,7 @@ static void get_openreq4(const struct sock *sk, const struct request_sock *req,
TCP_SYN_RECV,
0, 0, /* could print option size, but that is af dependent. */
1, /* timers active (only the expire timer) */
- jiffies_to_clock_t(ttd),
+ jiffies_delta_to_clock_t(delta),
req->retrans,
from_kuid_munged(seq_user_ns(f), uid),
0, /* non standard timer */
@@ -2425,6 +2654,7 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
const struct tcp_sock *tp = tcp_sk(sk);
const struct inet_connection_sock *icsk = inet_csk(sk);
const struct inet_sock *inet = inet_sk(sk);
+ struct fastopen_queue *fastopenq = icsk->icsk_accept_queue.fastopenq;
__be32 dest = inet->inet_daddr;
__be32 src = inet->inet_rcv_saddr;
__u16 destp = ntohs(inet->inet_dport);
@@ -2459,7 +2689,7 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
tp->write_seq - tp->snd_una,
rx_queue,
timer_active,
- jiffies_to_clock_t(timer_expires - jiffies),
+ jiffies_delta_to_clock_t(timer_expires - jiffies),
icsk->icsk_retransmits,
from_kuid_munged(seq_user_ns(f), sock_i_uid(sk)),
icsk->icsk_probes_out,
@@ -2469,7 +2699,9 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i, int *len)
jiffies_to_clock_t(icsk->icsk_ack.ato),
(icsk->icsk_ack.quick << 1) | icsk->icsk_ack.pingpong,
tp->snd_cwnd,
- tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh,
+ sk->sk_state == TCP_LISTEN ?
+ (fastopenq ? fastopenq->max_qlen : 0) :
+ (tcp_in_initial_slowstart(tp) ? -1 : tp->snd_ssthresh),
len);
}
@@ -2478,10 +2710,7 @@ static void get_timewait4_sock(const struct inet_timewait_sock *tw,
{
__be32 dest, src;
__u16 destp, srcp;
- int ttd = tw->tw_ttd - jiffies;
-
- if (ttd < 0)
- ttd = 0;
+ long delta = tw->tw_ttd - jiffies;
dest = tw->tw_daddr;
src = tw->tw_rcv_saddr;
@@ -2491,7 +2720,7 @@ static void get_timewait4_sock(const struct inet_timewait_sock *tw,
seq_printf(f, "%4d: %08X:%04X %08X:%04X"
" %02X %08X:%08X %02X:%08lX %08X %5d %8d %d %d %pK%n",
i, src, srcp, dest, destp, tw->tw_substate, 0, 0,
- 3, jiffies_to_clock_t(ttd), 0, 0, 0, 0,
+ 3, jiffies_delta_to_clock_t(delta), 0, 0, 0, 0,
atomic_read(&tw->tw_refcnt), tw, len);
}
@@ -2574,6 +2803,8 @@ void tcp4_proc_exit(void)
struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
{
const struct iphdr *iph = skb_gro_network_header(skb);
+ __wsum wsum;
+ __sum16 sum;
switch (skb->ip_summed) {
case CHECKSUM_COMPLETE:
@@ -2582,11 +2813,22 @@ struct sk_buff **tcp4_gro_receive(struct sk_buff **head, struct sk_buff *skb)
skb->ip_summed = CHECKSUM_UNNECESSARY;
break;
}
-
- /* fall through */
- case CHECKSUM_NONE:
+flush:
NAPI_GRO_CB(skb)->flush = 1;
return NULL;
+
+ case CHECKSUM_NONE:
+ wsum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
+ skb_gro_len(skb), IPPROTO_TCP, 0);
+ sum = csum_fold(skb_checksum(skb,
+ skb_gro_offset(skb),
+ skb_gro_len(skb),
+ wsum));
+ if (sum)
+ goto flush;
+
+ skb->ip_summed = CHECKSUM_UNNECESSARY;
+ break;
}
return tcp_gro_receive(head, skb);