1 files changed, 34 insertions, 0 deletions

diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index e6215bdd96c0..a1151b8adf3c 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -45,6 +45,7 @@
 #include <linux/udp.h>
 #include <linux/inet.h>
 #include <linux/netfilter_ipv4.h>
+#include <net/inet_ecn.h>
 
 /* NOTE. Logic of IP defragmentation is parallel to corresponding IPv6
  * code now. If you change something here, _PLEASE_ update ipv6/reassembly.c
@@ -70,11 +71,28 @@ struct ipq {
         __be32          daddr;
         __be16          id;
         u8              protocol;
+        u8              ecn; /* RFC3168 support */
         int             iif;
         unsigned int    rid;
         struct inet_peer *peer;
 };
 
+#define IPFRAG_ECN_CLEAR  0x01 /* one frag had INET_ECN_NOT_ECT */
+#define IPFRAG_ECN_SET_CE 0x04 /* one frag had INET_ECN_CE */
+
+static inline u8 ip4_frag_ecn(u8 tos)
+{
+        tos = (tos & INET_ECN_MASK) + 1;
+        /*
+         * After the last operation we have (in binary):
+         * INET_ECN_NOT_ECT => 001
+         * INET_ECN_ECT_1   => 010
+         * INET_ECN_ECT_0   => 011
+         * INET_ECN_CE      => 100
+         */
+        return (tos & 2) ? 0 : tos;
+}
+
 static struct inet_frags ip4_frags;
 
 int ip_frag_nqueues(struct net *net)
@@ -137,6 +155,7 @@ static void ip4_frag_init(struct inet_frag_queue *q, void *a)
 
         qp->protocol = arg->iph->protocol;
         qp->id = arg->iph->id;
+        qp->ecn = ip4_frag_ecn(arg->iph->tos);
         qp->saddr = arg->iph->saddr;
         qp->daddr = arg->iph->daddr;
         qp->user = arg->user;
@@ -316,6 +335,7 @@ static int ip_frag_reinit(struct ipq *qp)
         qp->q.fragments = NULL;
         qp->q.fragments_tail = NULL;
         qp->iif = 0;
+        qp->ecn = 0;
 
         return 0;
 }
@@ -328,6 +348,7 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
         int flags, offset;
         int ihl, end;
         int err = -ENOENT;
+        u8 ecn;
 
         if (qp->q.last_in & INET_FRAG_COMPLETE)
                 goto err;
@@ -339,6 +360,7 @@ static int ip_frag_queue(struct ipq *qp, struct sk_buff *skb)
                 goto err;
         }
 
+        ecn = ip4_frag_ecn(ip_hdr(skb)->tos);
         offset = ntohs(ip_hdr(skb)->frag_off);
         flags = offset & ~IP_OFFSET;
         offset &= IP_OFFSET;
@@ -472,6 +494,7 @@ found:
         }
         qp->q.stamp = skb->tstamp;
         qp->q.meat += skb->len;
+        qp->ecn |= ecn;
         atomic_add(skb->truesize, &qp->q.net->mem);
         if (offset == 0)
                 qp->q.last_in |= INET_FRAG_FIRST_IN;
@@ -583,6 +606,17 @@ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
         iph = ip_hdr(head);
         iph->frag_off = 0;
         iph->tot_len = htons(len);
+        /* RFC3168 5.3 Fragmentation support
+         * If one fragment had INET_ECN_NOT_ECT,
+         *      reassembled frame also has INET_ECN_NOT_ECT
+         * Elif one fragment had INET_ECN_CE
+         *      reassembled frame also has INET_ECN_CE
+         */
+        if (qp->ecn & IPFRAG_ECN_CLEAR)
+                iph->tos &= ~INET_ECN_MASK;
+        else if (qp->ecn & IPFRAG_ECN_SET_CE)
+                iph->tos |= INET_ECN_CE;
+
         IP_INC_STATS_BH(net, IPSTATS_MIB_REASMOKS);
         qp->q.fragments = NULL;
         qp->q.fragments_tail = NULL;