diff options
| author | Tom Herbert <therbert@google.com> | 2014-06-04 17:19:48 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-06-04 22:46:38 -0700 |
| commit | af5fcba7f38f3166392f4087ab734433c84f160b (patch) | |
| tree | 8a6deba10cd458a72e159112ab6381bcaa352b3e /net/ipv4 | |
| parent | 6579867c8b02606e101a6c511c2511b027ed3f4a (diff) | |
| download | linux-af5fcba7f38f3166392f4087ab734433c84f160b.tar.bz2 | |
udp: Generic functions to set checksum
Added udp_set_csum and udp6_set_csum functions to set UDP checksums
in packets. These are for simple UDP packets such as those that might
be created in UDP tunnels.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/udp.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index e07d52b8617a..a84f6762ea9e 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -762,6 +762,43 @@ void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst) } EXPORT_SYMBOL_GPL(udp4_hwcsum); +/* Function to set UDP checksum for an IPv4 UDP packet. This is intended + * for the simple case like when setting the checksum for a UDP tunnel. + */ +void udp_set_csum(bool nocheck, struct sk_buff *skb, + __be32 saddr, __be32 daddr, int len) +{ + struct udphdr *uh = udp_hdr(skb); + + if (nocheck) + uh->check = 0; + else if (skb_is_gso(skb)) + uh->check = ~udp_v4_check(len, saddr, daddr, 0); + else if (skb_dst(skb) && skb_dst(skb)->dev && + (skb_dst(skb)->dev->features & NETIF_F_V4_CSUM)) { + + BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL); + + skb->ip_summed = CHECKSUM_PARTIAL; + skb->csum_start = skb_transport_header(skb) - skb->head; + skb->csum_offset = offsetof(struct udphdr, check); + uh->check = ~udp_v4_check(len, saddr, daddr, 0); + } else { + __wsum csum; + + BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL); + + uh->check = 0; + csum = skb_checksum(skb, 0, len, 0); + uh->check = udp_v4_check(len, saddr, daddr, csum); + if (uh->check == 0) + uh->check = CSUM_MANGLED_0; + + skb->ip_summed = CHECKSUM_UNNECESSARY; + } +} +EXPORT_SYMBOL(udp_set_csum); + static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4) { struct sock *sk = skb->sk; |