| Message ID | d67799da9624127ffabf05226c0f20090be4f785.1310601401.git.mirq-linux@rere.qmqm.pl |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Michał Mirosław <mirq-linux@rere.qmqm.pl> Date: Thu, 14 Jul 2011 02:10:29 +0200 (CEST) > Packets to devices without NETIF_F_SCTP_CSUM (including NETIF_F_NO_CSUM) > should be properly checksummed because the packets can be diverted or > rerouted after construction. This still leaves packets diverted from > NETIF_F_SCTP_CSUM-enabled devices with broken checksums. Fixing this > needs implementing software offload fallback in networking core. > > For users of sctp_checksum_disable, skb->ip_summed should be left as > CHECKSUM_NONE and not CHECKSUM_UNNECESSARY as per include/linux/skbuff.h. > > Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl> This is not the way to fix this. We need to add the proper software fallback when the SKB device changes to one with SCTP/NO_CSUM to one that does not. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/sctp/output.c b/net/sctp/output.c index b4f3cf0..08b3cea 100644 --- a/net/sctp/output.c +++ b/net/sctp/output.c @@ -500,23 +500,20 @@ int sctp_packet_transmit(struct sctp_packet *packet) * Note: Adler-32 is no longer applicable, as has been replaced * by CRC32-C as described in <draft-ietf-tsvwg-sctpcsum-02.txt>. */ - if (!sctp_checksum_disable && - !(dst->dev->features & (NETIF_F_NO_CSUM | NETIF_F_SCTP_CSUM))) { - __u32 crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len); + if (!sctp_checksum_disable) { + if (!(dst->dev->features & NETIF_F_SCTP_CSUM)) { + __u32 crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len); - /* 3) Put the resultant value into the checksum field in the - * common header, and leave the rest of the bits unchanged. - */ - sh->checksum = sctp_end_cksum(crc32); - } else { - if (dst->dev->features & NETIF_F_SCTP_CSUM) { + /* 3) Put the resultant value into the checksum field in the + * common header, and leave the rest of the bits unchanged. + */ + sh->checksum = sctp_end_cksum(crc32); + } else { /* no need to seed pseudo checksum for SCTP */ nskb->ip_summed = CHECKSUM_PARTIAL; nskb->csum_start = (skb_transport_header(nskb) - nskb->head); nskb->csum_offset = offsetof(struct sctphdr, checksum); - } else { - nskb->ip_summed = CHECKSUM_UNNECESSARY; } }
Packets to devices without NETIF_F_SCTP_CSUM (including NETIF_F_NO_CSUM) should be properly checksummed because the packets can be diverted or rerouted after construction. This still leaves packets diverted from NETIF_F_SCTP_CSUM-enabled devices with broken checksums. Fixing this needs implementing software offload fallback in networking core. For users of sctp_checksum_disable, skb->ip_summed should be left as CHECKSUM_NONE and not CHECKSUM_UNNECESSARY as per include/linux/skbuff.h. Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl> --- net/sctp/output.c | 19 ++++++++----------- 1 files changed, 8 insertions(+), 11 deletions(-)