1 #include <linux/version.h>
3 #ifndef HAVE_UDP_SET_CSUM
7 /* Function to set UDP checksum for an IPv4 UDP packet. This is intended
8 * for the simple case like when setting the checksum for a UDP tunnel.
10 void udp_set_csum(bool nocheck, struct sk_buff *skb,
11 __be32 saddr, __be32 daddr, int len)
13 struct udphdr *uh = udp_hdr(skb);
17 else if (skb_is_gso(skb))
18 uh->check = ~udp_v4_check(len, saddr, daddr, 0);
19 else if (skb_dst(skb) && skb_dst(skb)->dev &&
20 (skb_dst(skb)->dev->features & NETIF_F_V4_CSUM)) {
22 BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL);
24 skb->ip_summed = CHECKSUM_PARTIAL;
25 skb->csum_start = skb_transport_header(skb) - skb->head;
26 skb->csum_offset = offsetof(struct udphdr, check);
27 uh->check = ~udp_v4_check(len, saddr, daddr, 0);
31 BUG_ON(skb->ip_summed == CHECKSUM_PARTIAL);
34 csum = skb_checksum(skb, 0, len, 0);
35 uh->check = udp_v4_check(len, saddr, daddr, csum);
37 uh->check = CSUM_MANGLED_0;
39 skb->ip_summed = CHECKSUM_UNNECESSARY;
43 #endif /* Linux version < 3.16 */