diff options
| author | Ed Swierk <eswierk@skyportsystems.com> | 2017-11-16 06:06:06 -0800 |
|---|---|---|
| committer | Jason Wang <jasowang@redhat.com> | 2017-11-20 11:08:00 +0800 |
| commit | 0dacea92d26c31d453c58de2e99c178fee554166 (patch) | |
| tree | 5b8fd0c05385e02a586fbc136808821e603ea14f /hw/net | |
| parent | ebc2327f0793deed845e2f7aeddf43b367c5c71c (diff) | |
net: Transmit zero UDP checksum as 0xFFFF
The checksum algorithm used by IPv4, TCP and UDP allows a zero value
to be represented by either 0x0000 and 0xFFFF. But per RFC 768, a zero
UDP checksum must be transmitted as 0xFFFF because 0x0000 is a special
value meaning no checksum.
Substitute 0xFFFF whenever a checksum is computed as zero when
modifying a UDP datagram header. Doing this on IPv4 and TCP checksums
is unnecessary but legal. Add a wrapper for net_checksum_finish() that
makes the substitution.
(We can't just change net_checksum_finish(), as that function is also
used by receivers to verify checksums, and in that case the expected
value is always 0x0000.)
Signed-off-by: Ed Swierk <eswierk@skyportsystems.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Diffstat (limited to 'hw/net')
| -rw-r--r-- | hw/net/e1000.c | 2 | ||||
| -rw-r--r-- | hw/net/net_rx_pkt.c | 2 | ||||
| -rw-r--r-- | hw/net/net_tx_pkt.c | 2 | ||||
| -rw-r--r-- | hw/net/vmxnet3.c | 3 |
4 files changed, 5 insertions, 4 deletions
diff --git a/hw/net/e1000.c b/hw/net/e1000.c index c0abee4f7e..05a00cba31 100644 --- a/hw/net/e1000.c +++ b/hw/net/e1000.c @@ -503,7 +503,7 @@ putsum(uint8_t *data, uint32_t n, uint32_t sloc, uint32_t css, uint32_t cse) n = cse + 1; if (sloc < n-1) { sum = net_checksum_add(n-css, data+css); - stw_be_p(data + sloc, net_checksum_finish(sum)); + stw_be_p(data + sloc, net_checksum_finish_nozero(sum)); } } diff --git a/hw/net/net_rx_pkt.c b/hw/net/net_rx_pkt.c index cef1c2e0d1..98a5030ace 100644 --- a/hw/net/net_rx_pkt.c +++ b/hw/net/net_rx_pkt.c @@ -518,7 +518,7 @@ _net_rx_pkt_calc_l4_csum(struct NetRxPkt *pkt) cntr += net_checksum_add_iov(pkt->vec, pkt->vec_len, pkt->l4hdr_off, csl, cso); - csum = net_checksum_finish(cntr); + csum = net_checksum_finish_nozero(cntr); trace_net_rx_pkt_l4_csum_calc_csum(pkt->l4hdr_off, csl, cntr, csum); diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c index 20b25496e5..e29c881bc2 100644 --- a/hw/net/net_tx_pkt.c +++ b/hw/net/net_tx_pkt.c @@ -486,7 +486,7 @@ static void net_tx_pkt_do_sw_csum(struct NetTxPkt *pkt) net_checksum_add_iov(iov, iov_len, pkt->virt_hdr.csum_start, csl, cso); /* Put the checksum obtained into the packet */ - csum = cpu_to_be16(net_checksum_finish(csum_cntr)); + csum = cpu_to_be16(net_checksum_finish_nozero(csum_cntr)); iov_from_buf(iov, iov_len, csum_offset, &csum, sizeof csum); } diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c index 8c4bae5394..cdc307dd04 100644 --- a/hw/net/vmxnet3.c +++ b/hw/net/vmxnet3.c @@ -972,7 +972,8 @@ static void vmxnet3_rx_need_csum_calculate(struct NetRxPkt *pkt, data = (uint8_t *)pkt_data + vhdr->csum_start; len = pkt_len - vhdr->csum_start; /* Put the checksum obtained into the packet */ - stw_be_p(data + vhdr->csum_offset, net_raw_checksum(data, len)); + stw_be_p(data + vhdr->csum_offset, + net_checksum_finish_nozero(net_checksum_add(len, data))); vhdr->flags &= ~VIRTIO_NET_HDR_F_NEEDS_CSUM; vhdr->flags |= VIRTIO_NET_HDR_F_DATA_VALID; |