/* * IPV6 GSO/GRO offload support * Linux INET6 implementation * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * UDPv6 GSO support */ #include <linux/skbuff.h> #include <net/protocol.h> #include <net/ipv6.h> #include <net/udp.h> #include <net/ip6_checksum.h> #include "ip6_offload.h" static int udp6_ufo_send_check(struct sk_buff *skb) { const struct ipv6hdr *ipv6h; struct udphdr *uh; /* UDP Tunnel offload on ipv6 is not yet supported. */ if (skb->encapsulation) return -EINVAL; if (!pskb_may_pull(skb, sizeof(*uh))) return -EINVAL; ipv6h = ipv6_hdr(skb); uh = udp_hdr(skb); uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len, IPPROTO_UDP, 0); skb->csum_start = skb_transport_header(skb) - skb->head; skb->csum_offset = offsetof(struct udphdr, check); skb->ip_summed = CHECKSUM_PARTIAL; return 0; } static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, netdev_features_t features) { struct sk_buff *segs = ERR_PTR(-EINVAL); unsigned int mss; unsigned int unfrag_ip6hlen, unfrag_len; struct frag_hdr *fptr; u8 *mac_start, *prevhdr; u8 nexthdr; u8 frag_hdr_sz = sizeof(struct frag_hdr); int offset; __wsum csum; mss = skb_shinfo(skb)->gso_size; if (unlikely(skb->len <= mss)) goto out; if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { /* Packet is from an untrusted source, reset gso_segs. */ int type = skb_shinfo(skb)->gso_type; if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY | SKB_GSO_UDP_TUNNEL | SKB_GSO_GRE) || !(type & (SKB_GSO_UDP)))) goto out; skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); segs = NULL; goto out; } /* Do software UFO. Complete and fill in the UDP checksum as HW cannot * do checksum of UDP packets sent as multiple IP fragments. */ offset = skb_checksum_start_offset(skb); csum = skb_checksum(skb, offset, skb->len - offset, 0); offset += skb->csum_offset; *(__sum16 *)(skb->data + offset) = csum_fold(csum); skb->ip_summed = CHECKSUM_NONE; /* Check if there is enough headroom to insert fragment header. */ if ((skb_mac_header(skb) < skb->head + frag_hdr_sz) && pskb_expand_head(skb, frag_hdr_sz, 0, GFP_ATOMIC)) goto out; /* Find the unfragmentable header and shift it left by frag_hdr_sz * bytes to insert fragment header. */ unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr); nexthdr = *prevhdr; *prevhdr = NEXTHDR_FRAGMENT; unfrag_len = skb_network_header(skb) - skb_mac_header(skb) + unfrag_ip6hlen; mac_start = skb_mac_header(skb); memmove(mac_start-frag_hdr_sz, mac_start, unfrag_len); skb->mac_header -= frag_hdr_sz; skb->network_header -= frag_hdr_sz; fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen); fptr->nexthdr = nexthdr; fptr->reserved = 0; ipv6_select_ident(fptr, (struct rt6_info *)skb_dst(skb)); /* Fragment the skb. ipv6 header and the remaining fields of the * fragment header are updated in ipv6_gso_segment() */ segs = skb_segment(skb, features); out: return segs; } static const struct net_offload udpv6_offload = { .callbacks = { .gso_send_check = udp6_ufo_send_check, .gso_segment = udp6_ufo_fragment, }, }; int __init udp_offload_init(void) { return inet6_add_offload(&udpv6_offload, IPPROTO_UDP); }