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Commit b73c43f8 authored by Michał Mirosław's avatar Michał Mirosław Committed by David S. Miller
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net: sctp: fix checksum marking for outgoing packets 



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: default avatarMichał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 51414d41

net/sctp/output.c

+8 −11
Original line number Diff line number Diff line
@@ -500,8 +500,8 @@ 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	 * Note: Adler-32 is no longer applicable, as has been replaced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))) {

	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
@@ -509,14 +509,11 @@ int sctp_packet_transmit(struct sctp_packet *packet) 
			 */

			sh->checksum = sctp_end_cksum(crc32);

		} else {

		if (dst->dev->features & NETIF_F_SCTP_CSUM) {

			/* 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;

		}

	}