1 /* 2 * IPV6 GSO/GRO offload support 3 * Linux INET6 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 * UDPv6 GSO support 11 */ 12 #include <linux/skbuff.h> 13 #include <linux/netdevice.h> 14 #include <linux/indirect_call_wrapper.h> 15 #include <net/protocol.h> 16 #include <net/ipv6.h> 17 #include <net/udp.h> 18 #include <net/ip6_checksum.h> 19 #include "ip6_offload.h" 20 21 static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, 22 netdev_features_t features) 23 { 24 struct sk_buff *segs = ERR_PTR(-EINVAL); 25 unsigned int mss; 26 unsigned int unfrag_ip6hlen, unfrag_len; 27 struct frag_hdr *fptr; 28 u8 *packet_start, *prevhdr; 29 u8 nexthdr; 30 u8 frag_hdr_sz = sizeof(struct frag_hdr); 31 __wsum csum; 32 int tnl_hlen; 33 int err; 34 35 mss = skb_shinfo(skb)->gso_size; 36 if (unlikely(skb->len <= mss)) 37 goto out; 38 39 if (skb->encapsulation && skb_shinfo(skb)->gso_type & 40 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM)) 41 segs = skb_udp_tunnel_segment(skb, features, true); 42 else { 43 const struct ipv6hdr *ipv6h; 44 struct udphdr *uh; 45 46 if (!(skb_shinfo(skb)->gso_type & (SKB_GSO_UDP | SKB_GSO_UDP_L4))) 47 goto out; 48 49 if (!pskb_may_pull(skb, sizeof(struct udphdr))) 50 goto out; 51 52 if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) 53 return __udp_gso_segment(skb, features); 54 55 /* Do software UFO. Complete and fill in the UDP checksum as HW cannot 56 * do checksum of UDP packets sent as multiple IP fragments. 57 */ 58 59 uh = udp_hdr(skb); 60 ipv6h = ipv6_hdr(skb); 61 62 uh->check = 0; 63 csum = skb_checksum(skb, 0, skb->len, 0); 64 uh->check = udp_v6_check(skb->len, &ipv6h->saddr, 65 &ipv6h->daddr, csum); 66 if (uh->check == 0) 67 uh->check = CSUM_MANGLED_0; 68 69 skb->ip_summed = CHECKSUM_UNNECESSARY; 70 71 /* If there is no outer header we can fake a checksum offload 72 * due to the fact that we have already done the checksum in 73 * software prior to segmenting the frame. 74 */ 75 if (!skb->encap_hdr_csum) 76 features |= NETIF_F_HW_CSUM; 77 78 /* Check if there is enough headroom to insert fragment header. */ 79 tnl_hlen = skb_tnl_header_len(skb); 80 if (skb->mac_header < (tnl_hlen + frag_hdr_sz)) { 81 if (gso_pskb_expand_head(skb, tnl_hlen + frag_hdr_sz)) 82 goto out; 83 } 84 85 /* Find the unfragmentable header and shift it left by frag_hdr_sz 86 * bytes to insert fragment header. 87 */ 88 err = ip6_find_1stfragopt(skb, &prevhdr); 89 if (err < 0) 90 return ERR_PTR(err); 91 unfrag_ip6hlen = err; 92 nexthdr = *prevhdr; 93 *prevhdr = NEXTHDR_FRAGMENT; 94 unfrag_len = (skb_network_header(skb) - skb_mac_header(skb)) + 95 unfrag_ip6hlen + tnl_hlen; 96 packet_start = (u8 *) skb->head + SKB_GSO_CB(skb)->mac_offset; 97 memmove(packet_start-frag_hdr_sz, packet_start, unfrag_len); 98 99 SKB_GSO_CB(skb)->mac_offset -= frag_hdr_sz; 100 skb->mac_header -= frag_hdr_sz; 101 skb->network_header -= frag_hdr_sz; 102 103 fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen); 104 fptr->nexthdr = nexthdr; 105 fptr->reserved = 0; 106 fptr->identification = ipv6_proxy_select_ident(dev_net(skb->dev), skb); 107 108 /* Fragment the skb. ipv6 header and the remaining fields of the 109 * fragment header are updated in ipv6_gso_segment() 110 */ 111 segs = skb_segment(skb, features); 112 } 113 114 out: 115 return segs; 116 } 117 118 INDIRECT_CALLABLE_SCOPE 119 struct sk_buff *udp6_gro_receive(struct list_head *head, struct sk_buff *skb) 120 { 121 struct udphdr *uh = udp_gro_udphdr(skb); 122 123 if (unlikely(!uh) || !static_branch_unlikely(&udpv6_encap_needed_key)) 124 goto flush; 125 126 /* Don't bother verifying checksum if we're going to flush anyway. */ 127 if (NAPI_GRO_CB(skb)->flush) 128 goto skip; 129 130 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check, 131 ip6_gro_compute_pseudo)) 132 goto flush; 133 else if (uh->check) 134 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check, 135 ip6_gro_compute_pseudo); 136 137 skip: 138 NAPI_GRO_CB(skb)->is_ipv6 = 1; 139 return udp_gro_receive(head, skb, uh, udp6_lib_lookup_skb); 140 141 flush: 142 NAPI_GRO_CB(skb)->flush = 1; 143 return NULL; 144 } 145 146 INDIRECT_CALLABLE_SCOPE int udp6_gro_complete(struct sk_buff *skb, int nhoff) 147 { 148 const struct ipv6hdr *ipv6h = ipv6_hdr(skb); 149 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); 150 151 if (uh->check) 152 uh->check = ~udp_v6_check(skb->len - nhoff, &ipv6h->saddr, 153 &ipv6h->daddr, 0); 154 155 return udp_gro_complete(skb, nhoff, udp6_lib_lookup_skb); 156 } 157 158 static const struct net_offload udpv6_offload = { 159 .callbacks = { 160 .gso_segment = udp6_ufo_fragment, 161 .gro_receive = udp6_gro_receive, 162 .gro_complete = udp6_gro_complete, 163 }, 164 }; 165 166 int udpv6_offload_init(void) 167 { 168 return inet6_add_offload(&udpv6_offload, IPPROTO_UDP); 169 } 170 171 int udpv6_offload_exit(void) 172 { 173 return inet6_del_offload(&udpv6_offload, IPPROTO_UDP); 174 } 175