[DCCP]: Retrieve packet sequence number for error reporting
This fixes a problem when analysing erroneous packets in dccp_v{4,6}_err:
* dccp_hdr_seq currently takes an skb
* however, the transport headers in the skb are shifted, due to the
preceding ICMPv4/v6 header.
Fixed for v4 and v6 by changing dccp_hdr_seq to take a struct dccp_hdr as
argument. Verified that the correct sequence number is now reported in the
error handler.
Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
---
include/linux/dccp.h | 10 ++++------
net/dccp/ipv4.c | 4 ++--
net/dccp/ipv6.c | 4 ++--
3 files changed, 8 insertions(+), 10 deletions(-)
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -271,10 +271,9 @@ static inline struct dccp_hdr *dccp_zero
return memset(skb_transport_header(skb), 0, headlen);
}
-static inline struct dccp_hdr_ext *dccp_hdrx(const struct sk_buff *skb)
+static inline struct dccp_hdr_ext *dccp_hdrx(const struct dccp_hdr *dh)
{
- return (struct dccp_hdr_ext *)(skb_transport_header(skb) +
- sizeof(struct dccp_hdr));
+ return (struct dccp_hdr_ext *)((unsigned char *)dh + sizeof(*dh));
}
static inline unsigned int __dccp_basic_hdr_len(const struct dccp_hdr *dh)
@@ -288,13 +287,12 @@ static inline unsigned int dccp_basic_hd
return __dccp_basic_hdr_len(dh);
}
-static inline __u64 dccp_hdr_seq(const struct sk_buff *skb)
+static inline __u64 dccp_hdr_seq(const struct dccp_hdr *dh)
{
- const struct dccp_hdr *dh = dccp_hdr(skb);
__u64 seq_nr = ntohs(dh->dccph_seq);
if (dh->dccph_x != 0)
- seq_nr = (seq_nr << 32) + ntohl(dccp_hdrx(skb)->dccph_seq_low);
+ seq_nr = (seq_nr << 32) + ntohl(dccp_hdrx(dh)->dccph_seq_low);
else
seq_nr += (u32)dh->dccph_seq2 << 16;
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -241,7 +241,7 @@ static void dccp_v4_err(struct sk_buff *
goto out;
dp = dccp_sk(sk);
- seq = dccp_hdr_seq(skb);
+ seq = dccp_hdr_seq(dh);
if (sk->sk_state != DCCP_LISTEN &&
!between48(seq, dp->dccps_swl, dp->dccps_swh)) {
NET_INC_STATS_BH(LINUX_MIB_OUTOFWINDOWICMPS);
@@ -828,7 +828,7 @@ static int dccp_v4_rcv(struct sk_buff *s
dh = dccp_hdr(skb);
- DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(skb);
+ DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
dccp_pr_debug("%8.8s "
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -173,7 +173,7 @@ static void dccp_v6_err(struct sk_buff *
icmpv6_err_convert(type, code, &err);
- seq = DCCP_SKB_CB(skb)->dccpd_seq;
+ seq = dccp_hdr_seq(dh);
/* Might be for an request_sock */
switch (sk->sk_state) {
struct request_sock *req, **prev;
@@ -816,7 +816,7 @@ static int dccp_v6_rcv(struct sk_buff **
dh = dccp_hdr(skb);
- DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(skb);
+ DCCP_SKB_CB(skb)->dccpd_seq = dccp_hdr_seq(dh);
DCCP_SKB_CB(skb)->dccpd_type = dh->dccph_type;
if (dccp_packet_without_ack(skb))
-
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