252 lines
8.6 KiB
Diff
252 lines
8.6 KiB
Diff
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
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index 709d24b4b533..21ad4f3cece8 100644
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--- a/Documentation/networking/ip-sysctl.txt
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+++ b/Documentation/networking/ip-sysctl.txt
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@@ -220,6 +220,14 @@ tcp_base_mss - INTEGER
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Path MTU discovery (MTU probing). If MTU probing is enabled,
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this is the initial MSS used by the connection.
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+tcp_min_snd_mss - INTEGER
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+ TCP SYN and SYNACK messages usually advertise an ADVMSS option,
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+ as described in RFC 1122 and RFC 6691.
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+ If this ADVMSS option is smaller than tcp_min_snd_mss,
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+ it is silently capped to tcp_min_snd_mss.
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+
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+ Default : 48 (at least 8 bytes of payload per segment)
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+
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tcp_congestion_control - STRING
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Set the congestion control algorithm to be used for new
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connections. The algorithm "reno" is always available, but
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diff --git a/Makefile b/Makefile
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index b33f3ecf84fc..fcfede5e39de 100644
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--- a/Makefile
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+++ b/Makefile
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@@ -1,6 +1,6 @@
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VERSION = 4
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PATCHLEVEL = 4
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-SUBLEVEL = 181
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+SUBLEVEL = 182
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EXTRAVERSION =
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NAME = Blurry Fish Butt
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diff --git a/include/linux/tcp.h b/include/linux/tcp.h
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index 747404dbe506..085da1707cea 100644
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--- a/include/linux/tcp.h
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+++ b/include/linux/tcp.h
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@@ -419,4 +419,7 @@ static inline void tcp_saved_syn_free(struct tcp_sock *tp)
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tp->saved_syn = NULL;
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}
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+int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from, int pcount,
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+ int shiftlen);
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+
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#endif /* _LINUX_TCP_H */
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diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
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index c68926b4899c..61c38f87ea07 100644
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--- a/include/net/netns/ipv4.h
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+++ b/include/net/netns/ipv4.h
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@@ -88,6 +88,7 @@ struct netns_ipv4 {
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int sysctl_tcp_fwmark_accept;
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int sysctl_tcp_mtu_probing;
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int sysctl_tcp_base_mss;
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+ int sysctl_tcp_min_snd_mss;
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int sysctl_tcp_probe_threshold;
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u32 sysctl_tcp_probe_interval;
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diff --git a/include/net/tcp.h b/include/net/tcp.h
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index 14ec97309581..bf8a0dae977a 100644
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--- a/include/net/tcp.h
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+++ b/include/net/tcp.h
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@@ -54,6 +54,8 @@ void tcp_time_wait(struct sock *sk, int state, int timeo);
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#define MAX_TCP_HEADER (128 + MAX_HEADER)
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#define MAX_TCP_OPTION_SPACE 40
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+#define TCP_MIN_SND_MSS 48
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+#define TCP_MIN_GSO_SIZE (TCP_MIN_SND_MSS - MAX_TCP_OPTION_SPACE)
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/*
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* Never offer a window over 32767 without using window scaling. Some
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diff --git a/include/uapi/linux/snmp.h b/include/uapi/linux/snmp.h
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index 9de808ebce05..422183f396d5 100644
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--- a/include/uapi/linux/snmp.h
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+++ b/include/uapi/linux/snmp.h
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@@ -281,6 +281,7 @@ enum
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LINUX_MIB_TCPKEEPALIVE, /* TCPKeepAlive */
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LINUX_MIB_TCPMTUPFAIL, /* TCPMTUPFail */
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LINUX_MIB_TCPMTUPSUCCESS, /* TCPMTUPSuccess */
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+ LINUX_MIB_TCPWQUEUETOOBIG, /* TCPWqueueTooBig */
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__LINUX_MIB_MAX
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};
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diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
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index b001ad668108..555586fc7840 100644
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--- a/net/ipv4/proc.c
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+++ b/net/ipv4/proc.c
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@@ -303,6 +303,7 @@ static const struct snmp_mib snmp4_net_list[] = {
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SNMP_MIB_ITEM("TCPKeepAlive", LINUX_MIB_TCPKEEPALIVE),
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SNMP_MIB_ITEM("TCPMTUPFail", LINUX_MIB_TCPMTUPFAIL),
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SNMP_MIB_ITEM("TCPMTUPSuccess", LINUX_MIB_TCPMTUPSUCCESS),
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+ SNMP_MIB_ITEM("TCPWqueueTooBig", LINUX_MIB_TCPWQUEUETOOBIG),
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SNMP_MIB_SENTINEL
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};
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diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
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index 167ca0fddf9e..6413e36d639d 100644
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--- a/net/ipv4/sysctl_net_ipv4.c
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+++ b/net/ipv4/sysctl_net_ipv4.c
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@@ -36,6 +36,8 @@ static int ip_local_port_range_min[] = { 1, 1 };
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static int ip_local_port_range_max[] = { 65535, 65535 };
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static int tcp_adv_win_scale_min = -31;
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static int tcp_adv_win_scale_max = 31;
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+static int tcp_min_snd_mss_min = TCP_MIN_SND_MSS;
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+static int tcp_min_snd_mss_max = 65535;
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static int ip_ttl_min = 1;
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static int ip_ttl_max = 255;
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static int tcp_syn_retries_min = 1;
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@@ -941,6 +943,15 @@ static struct ctl_table ipv4_net_table[] = {
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.mode = 0644,
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.proc_handler = proc_dointvec,
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},
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+ {
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+ .procname = "tcp_min_snd_mss",
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+ .data = &init_net.ipv4.sysctl_tcp_min_snd_mss,
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+ .maxlen = sizeof(int),
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+ .mode = 0644,
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+ .proc_handler = proc_dointvec_minmax,
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+ .extra1 = &tcp_min_snd_mss_min,
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+ .extra2 = &tcp_min_snd_mss_max,
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+ },
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{
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.procname = "tcp_probe_threshold",
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.data = &init_net.ipv4.sysctl_tcp_probe_threshold,
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diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
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index f3a4d2dcbf7a..303be2b76855 100644
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--- a/net/ipv4/tcp.c
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+++ b/net/ipv4/tcp.c
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@@ -3144,6 +3144,7 @@ void __init tcp_init(void)
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int max_rshare, max_wshare, cnt;
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unsigned int i;
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+ BUILD_BUG_ON(TCP_MIN_SND_MSS <= MAX_TCP_OPTION_SPACE);
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sock_skb_cb_check_size(sizeof(struct tcp_skb_cb));
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percpu_counter_init(&tcp_sockets_allocated, 0, GFP_KERNEL);
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diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
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index 44a3aa7a41e2..30c5500b0899 100644
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--- a/net/ipv4/tcp_input.c
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+++ b/net/ipv4/tcp_input.c
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@@ -1275,7 +1275,7 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *skb,
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TCP_SKB_CB(skb)->seq += shifted;
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tcp_skb_pcount_add(prev, pcount);
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- BUG_ON(tcp_skb_pcount(skb) < pcount);
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+ WARN_ON_ONCE(tcp_skb_pcount(skb) < pcount);
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tcp_skb_pcount_add(skb, -pcount);
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/* When we're adding to gso_segs == 1, gso_size will be zero,
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@@ -1337,6 +1337,21 @@ static int skb_can_shift(const struct sk_buff *skb)
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return !skb_headlen(skb) && skb_is_nonlinear(skb);
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}
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+int tcp_skb_shift(struct sk_buff *to, struct sk_buff *from,
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+ int pcount, int shiftlen)
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+{
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+ /* TCP min gso_size is 8 bytes (TCP_MIN_GSO_SIZE)
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+ * Since TCP_SKB_CB(skb)->tcp_gso_segs is 16 bits, we need
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+ * to make sure not storing more than 65535 * 8 bytes per skb,
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+ * even if current MSS is bigger.
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+ */
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+ if (unlikely(to->len + shiftlen >= 65535 * TCP_MIN_GSO_SIZE))
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+ return 0;
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+ if (unlikely(tcp_skb_pcount(to) + pcount > 65535))
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+ return 0;
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+ return skb_shift(to, from, shiftlen);
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+}
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+
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/* Try collapsing SACK blocks spanning across multiple skbs to a single
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* skb.
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*/
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@@ -1348,6 +1363,7 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
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struct tcp_sock *tp = tcp_sk(sk);
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struct sk_buff *prev;
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int mss;
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+ int next_pcount;
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int pcount = 0;
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int len;
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int in_sack;
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@@ -1442,7 +1458,7 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
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if (!after(TCP_SKB_CB(skb)->seq + len, tp->snd_una))
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goto fallback;
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- if (!skb_shift(prev, skb, len))
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+ if (!tcp_skb_shift(prev, skb, pcount, len))
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goto fallback;
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if (!tcp_shifted_skb(sk, skb, state, pcount, len, mss, dup_sack))
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goto out;
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@@ -1461,11 +1477,11 @@ static struct sk_buff *tcp_shift_skb_data(struct sock *sk, struct sk_buff *skb,
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goto out;
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len = skb->len;
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- if (skb_shift(prev, skb, len)) {
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- pcount += tcp_skb_pcount(skb);
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- tcp_shifted_skb(sk, skb, state, tcp_skb_pcount(skb), len, mss, 0);
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+ next_pcount = tcp_skb_pcount(skb);
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+ if (tcp_skb_shift(prev, skb, next_pcount, len)) {
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+ pcount += next_pcount;
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+ tcp_shifted_skb(sk, skb, state, next_pcount, len, mss, 0);
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}
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-
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out:
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state->fack_count += pcount;
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return prev;
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diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
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index b3d6b8e77300..744afb4fbf84 100644
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--- a/net/ipv4/tcp_ipv4.c
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+++ b/net/ipv4/tcp_ipv4.c
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@@ -2419,6 +2419,7 @@ static int __net_init tcp_sk_init(struct net *net)
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net->ipv4.sysctl_tcp_ecn_fallback = 1;
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net->ipv4.sysctl_tcp_base_mss = TCP_BASE_MSS;
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+ net->ipv4.sysctl_tcp_min_snd_mss = TCP_MIN_SND_MSS;
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net->ipv4.sysctl_tcp_probe_threshold = TCP_PROBE_THRESHOLD;
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net->ipv4.sysctl_tcp_probe_interval = TCP_PROBE_INTERVAL;
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diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
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index b55b8954dae5..bed83990847a 100644
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--- a/net/ipv4/tcp_output.c
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+++ b/net/ipv4/tcp_output.c
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@@ -1161,6 +1161,11 @@ int tcp_fragment(struct sock *sk, struct sk_buff *skb, u32 len,
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if (nsize < 0)
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nsize = 0;
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+ if (unlikely((sk->sk_wmem_queued >> 1) > sk->sk_sndbuf)) {
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+ NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPWQUEUETOOBIG);
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+ return -ENOMEM;
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+ }
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+
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if (skb_unclone(skb, gfp))
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return -ENOMEM;
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@@ -1327,8 +1332,7 @@ static inline int __tcp_mtu_to_mss(struct sock *sk, int pmtu)
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mss_now -= icsk->icsk_ext_hdr_len;
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/* Then reserve room for full set of TCP options and 8 bytes of data */
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- if (mss_now < 48)
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- mss_now = 48;
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+ mss_now = max(mss_now, sock_net(sk)->ipv4.sysctl_tcp_min_snd_mss);
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return mss_now;
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}
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diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
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index 35f638cfc675..61359944acc7 100644
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--- a/net/ipv4/tcp_timer.c
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+++ b/net/ipv4/tcp_timer.c
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@@ -132,6 +132,7 @@ static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk)
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mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low) >> 1;
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mss = min(net->ipv4.sysctl_tcp_base_mss, mss);
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mss = max(mss, 68 - tp->tcp_header_len);
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+ mss = max(mss, net->ipv4.sysctl_tcp_min_snd_mss);
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icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss);
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tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
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}
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