| Daniel Borkmann | da5bab0 | 2013-06-08 12:56:03 +0200 | [diff] [blame] | 1 | /* |
| 2 | * IPV4 GSO/GRO offload support |
| 3 | * Linux INET implementation |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU General Public License |
| 7 | * as published by the Free Software Foundation; either version |
| 8 | * 2 of the License, or (at your option) any later version. |
| 9 | * |
| 10 | * UDPv4 GSO support |
| 11 | */ |
| 12 | |
| 13 | #include <linux/skbuff.h> |
| 14 | #include <net/udp.h> |
| 15 | #include <net/protocol.h> |
| 16 | |
| 17 | static int udp4_ufo_send_check(struct sk_buff *skb) |
| 18 | { |
| 19 | if (!pskb_may_pull(skb, sizeof(struct udphdr))) |
| 20 | return -EINVAL; |
| 21 | |
| 22 | if (likely(!skb->encapsulation)) { |
| 23 | const struct iphdr *iph; |
| 24 | struct udphdr *uh; |
| 25 | |
| 26 | iph = ip_hdr(skb); |
| 27 | uh = udp_hdr(skb); |
| 28 | |
| 29 | uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len, |
| 30 | IPPROTO_UDP, 0); |
| 31 | skb->csum_start = skb_transport_header(skb) - skb->head; |
| 32 | skb->csum_offset = offsetof(struct udphdr, check); |
| 33 | skb->ip_summed = CHECKSUM_PARTIAL; |
| 34 | } |
| 35 | |
| 36 | return 0; |
| 37 | } |
| 38 | |
| 39 | static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, |
| 40 | netdev_features_t features) |
| 41 | { |
| 42 | struct sk_buff *segs = ERR_PTR(-EINVAL); |
| 43 | unsigned int mss; |
| 44 | |
| 45 | mss = skb_shinfo(skb)->gso_size; |
| 46 | if (unlikely(skb->len <= mss)) |
| 47 | goto out; |
| 48 | |
| 49 | if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { |
| 50 | /* Packet is from an untrusted source, reset gso_segs. */ |
| 51 | int type = skb_shinfo(skb)->gso_type; |
| 52 | |
| 53 | if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY | |
| 54 | SKB_GSO_UDP_TUNNEL | |
| 55 | SKB_GSO_GRE | SKB_GSO_MPLS) || |
| 56 | !(type & (SKB_GSO_UDP)))) |
| 57 | goto out; |
| 58 | |
| 59 | skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); |
| 60 | |
| 61 | segs = NULL; |
| 62 | goto out; |
| 63 | } |
| 64 | |
| 65 | /* Fragment the skb. IP headers of the fragments are updated in |
| 66 | * inet_gso_segment() |
| 67 | */ |
| 68 | if (skb->encapsulation && skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL) |
| 69 | segs = skb_udp_tunnel_segment(skb, features); |
| 70 | else { |
| 71 | int offset; |
| 72 | __wsum csum; |
| 73 | |
| 74 | /* Do software UFO. Complete and fill in the UDP checksum as |
| 75 | * HW cannot do checksum of UDP packets sent as multiple |
| 76 | * IP fragments. |
| 77 | */ |
| 78 | offset = skb_checksum_start_offset(skb); |
| 79 | csum = skb_checksum(skb, offset, skb->len - offset, 0); |
| 80 | offset += skb->csum_offset; |
| 81 | *(__sum16 *)(skb->data + offset) = csum_fold(csum); |
| 82 | skb->ip_summed = CHECKSUM_NONE; |
| 83 | |
| 84 | segs = skb_segment(skb, features); |
| 85 | } |
| 86 | out: |
| 87 | return segs; |
| 88 | } |
| 89 | |
| 90 | static const struct net_offload udpv4_offload = { |
| 91 | .callbacks = { |
| 92 | .gso_send_check = udp4_ufo_send_check, |
| 93 | .gso_segment = udp4_ufo_fragment, |
| 94 | }, |
| 95 | }; |
| 96 | |
| 97 | int __init udpv4_offload_init(void) |
| 98 | { |
| 99 | return inet_add_offload(&udpv4_offload, IPPROTO_UDP); |
| 100 | } |