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Diffstat (limited to 'net/ipv4/ip_fragment.c')
-rw-r--r--net/ipv4/ip_fragment.c60
1 files changed, 38 insertions, 22 deletions
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index b1d282f11be7..9e1458d3e465 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -77,22 +77,42 @@ struct ipq {
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 */
+/* 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.
+ */
+enum {
+ IPFRAG_ECN_NOT_ECT = 0x01, /* one frag had ECN_NOT_ECT */
+ IPFRAG_ECN_ECT_1 = 0x02, /* one frag had ECN_ECT_1 */
+ IPFRAG_ECN_ECT_0 = 0x04, /* one frag had ECN_ECT_0 */
+ IPFRAG_ECN_CE = 0x08, /* one frag had 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;
+ 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)
@@ -524,9 +544,15 @@ 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;
@@ -605,17 +631,7 @@ 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);
- /* 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;
-
+ iph->tos |= ecn;
IP_INC_STATS_BH(net, IPSTATS_MIB_REASMOKS);
qp->q.fragments = NULL;
qp->q.fragments_tail = NULL;