tcp: skip cwnd moderation in TCP_CA_Open in tcp_try_to_open
[linux-2.6.git] / net / ipv4 / ip_fragment.c
index e6215bd..fdaabf2 100644 (file)
@@ -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 +71,46 @@ struct ipq {
        __be32          daddr;
        __be16          id;
        u8              protocol;
+       u8              ecn; /* RFC3168 support */
        int             iif;
        unsigned int    rid;
        struct inet_peer *peer;
 };
 
+/* RFC 3168 support :
+ * We want to check ECN values of all fragments, do detect invalid combinations.
+ * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
+ */
+#define        IPFRAG_ECN_NOT_ECT      0x01 /* one frag had ECN_NOT_ECT */
+#define        IPFRAG_ECN_ECT_1        0x02 /* one frag had ECN_ECT_1 */
+#define        IPFRAG_ECN_ECT_0        0x04 /* one frag had ECN_ECT_0 */
+#define        IPFRAG_ECN_CE           0x08 /* one frag had ECN_CE */
+
+static inline u8 ip4_frag_ecn(u8 tos)
+{
+       return 1 << (tos & INET_ECN_MASK);
+}
+
+/* Given the OR values of all fragments, apply RFC 3168 5.3 requirements
+ * Value : 0xff if frame should be dropped.
+ *         0 or INET_ECN_CE value, to be ORed in to final iph->tos field
+ */
+static const u8 ip4_frag_ecn_table[16] = {
+       /* at least one fragment had CE, and others ECT_0 or ECT_1 */
+       [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0]                      = INET_ECN_CE,
+       [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1]                      = INET_ECN_CE,
+       [IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1]   = INET_ECN_CE,
+
+       /* invalid combinations : drop frame */
+       [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE] = 0xff,
+       [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0] = 0xff,
+       [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_1] = 0xff,
+       [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff,
+       [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0] = 0xff,
+       [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_1] = 0xff,
+       [IPFRAG_ECN_NOT_ECT | IPFRAG_ECN_CE | IPFRAG_ECN_ECT_0 | IPFRAG_ECN_ECT_1] = 0xff,
+};
+
 static struct inet_frags ip4_frags;
 
 int ip_frag_nqueues(struct net *net)
@@ -137,6 +173,7 @@ 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;
@@ -204,31 +241,31 @@ static void ip_expire(unsigned long arg)
 
        if ((qp->q.last_in & INET_FRAG_FIRST_IN) && qp->q.fragments != NULL) {
                struct sk_buff *head = qp->q.fragments;
+               const struct iphdr *iph;
+               int err;
 
                rcu_read_lock();
                head->dev = dev_get_by_index_rcu(net, qp->iif);
                if (!head->dev)
                        goto out_rcu_unlock;
 
+               /* skb dst is stale, drop it, and perform route lookup again */
+               skb_dst_drop(head);
+               iph = ip_hdr(head);
+               err = ip_route_input_noref(head, iph->daddr, iph->saddr,
+                                          iph->tos, head->dev);
+               if (err)
+                       goto out_rcu_unlock;
+
                /*
-                * Only search router table for the head fragment,
-                * when defraging timeout at PRE_ROUTING HOOK.
+                * Only an end host needs to send an ICMP
+                * "Fragment Reassembly Timeout" message, per RFC792.
                 */
-               if (qp->user == IP_DEFRAG_CONNTRACK_IN && !skb_dst(head)) {
-                       const struct iphdr *iph = ip_hdr(head);
-                       int err = ip_route_input(head, iph->daddr, iph->saddr,
-                                                iph->tos, head->dev);
-                       if (unlikely(err))
-                               goto out_rcu_unlock;
-
-                       /*
-                        * Only an end host needs to send an ICMP
-                        * "Fragment Reassembly Timeout" message, per RFC792.
-                        */
-                       if (skb_rtable(head)->rt_type != RTN_LOCAL)
-                               goto out_rcu_unlock;
+               if (qp->user == IP_DEFRAG_AF_PACKET ||
+                   (qp->user == IP_DEFRAG_CONNTRACK_IN &&
+                    skb_rtable(head)->rt_type != RTN_LOCAL))
+                       goto out_rcu_unlock;
 
-               }
 
                /* Send an ICMP "Fragment Reassembly Timeout" message. */
                icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0);
@@ -316,6 +353,7 @@ 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 +366,7 @@ 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 +378,7 @@ 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 +512,7 @@ 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;
@@ -502,9 +543,15 @@ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
        int len;
        int ihlen;
        int err;
+       u8 ecn;
 
        ipq_kill(qp);
 
+       ecn = ip4_frag_ecn_table[qp->ecn];
+       if (unlikely(ecn == 0xff)) {
+               err = -EINVAL;
+               goto out_fail;
+       }
        /* Make the one we just received the head. */
        if (prev) {
                head = prev->next;
@@ -552,8 +599,8 @@ static int ip_frag_reasm(struct ipq *qp, struct sk_buff *prev,
                head->next = clone;
                skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list;
                skb_frag_list_init(head);
-               for (i=0; i<skb_shinfo(head)->nr_frags; i++)
-                       plen += skb_shinfo(head)->frags[i].size;
+               for (i = 0; i < skb_shinfo(head)->nr_frags; i++)
+                       plen += skb_frag_size(&skb_shinfo(head)->frags[i]);
                clone->len = clone->data_len = head->data_len - plen;
                head->data_len -= clone->len;
                head->len -= clone->len;
@@ -583,6 +630,7 @@ 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);
+       iph->tos |= ecn;
        IP_INC_STATS_BH(net, IPSTATS_MIB_REASMOKS);
        qp->q.fragments = NULL;
        qp->q.fragments_tail = NULL;
@@ -634,6 +682,42 @@ int ip_defrag(struct sk_buff *skb, u32 user)
 }
 EXPORT_SYMBOL(ip_defrag);
 
+struct sk_buff *ip_check_defrag(struct sk_buff *skb, u32 user)
+{
+       const struct iphdr *iph;
+       u32 len;
+
+       if (skb->protocol != htons(ETH_P_IP))
+               return skb;
+
+       if (!pskb_may_pull(skb, sizeof(struct iphdr)))
+               return skb;
+
+       iph = ip_hdr(skb);
+       if (iph->ihl < 5 || iph->version != 4)
+               return skb;
+       if (!pskb_may_pull(skb, iph->ihl*4))
+               return skb;
+       iph = ip_hdr(skb);
+       len = ntohs(iph->tot_len);
+       if (skb->len < len || len < (iph->ihl * 4))
+               return skb;
+
+       if (ip_is_fragment(ip_hdr(skb))) {
+               skb = skb_share_check(skb, GFP_ATOMIC);
+               if (skb) {
+                       if (pskb_trim_rcsum(skb, len))
+                               return skb;
+                       memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
+                       if (ip_defrag(skb, user))
+                               return NULL;
+                       skb->rxhash = 0;
+               }
+       }
+       return skb;
+}
+EXPORT_SYMBOL(ip_check_defrag);
+
 #ifdef CONFIG_SYSCTL
 static int zero;