d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix a TSO checksum bug on mxge(4):

Browse Source 
The Myri10GE NIC will assume all TSO frames contain partial checksum,
and will emit TSO segments with bad TCP checksums if a TSO frame
contains a full checksum.  The mxge driver takes care to make sure
that TSO is disabled when checksum offload is disabled for this
reason.  However, modules that modify packet contents (like pf) may
end up completing a checksum on a TSO frame, leading to the NIC emitting
TSO segments with bad checksums.

To workaround this, restore the partial checksum in the mxge driver
when we're fed a TSO frame with a full checksum.

Reported by: Bob Healey

MFC after:	3 days
This commit is contained in:
gallatin 2010-11-22 16:43:05 +00:00
parent af24e6ed9f
commit 40b50edac3
1 changed files with 12 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
sys/dev/mxge/if_mxge.c
View File

@ -1855,9 +1855,20 @@ mxge_encap_tso(struct mxge_slice_state *ss, struct mbuf *m,
tcp = (struct tcphdr *)((char *)ip + (ip->ip_hl << 2));
cum_len = -(ip_off + ((ip->ip_hl + tcp->th_off) << 2));
cksum_offset = ip_off + (ip->ip_hl << 2);
/* TSO implies checksum offload on this hardware */
cksum_offset = ip_off + (ip->ip_hl << 2);
if (__predict_false((m->m_pkthdr.csum_flags & (CSUM_TCP)) == 0)) {
/*
* If packet has full TCP csum, replace it with pseudo hdr
* sum that the NIC expects, otherwise the NIC will emit
* packets with bad TCP checksums.
*/
m->m_pkthdr.csum_flags = CSUM_TCP;
m->m_pkthdr.csum_data = offsetof(struct tcphdr, th_sum);
tcp->th_sum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
htons(IPPROTO_TCP + (m->m_pkthdr.len - cksum_offset)));
}
flags = MXGEFW_FLAGS_TSO_HDR | MXGEFW_FLAGS_FIRST;