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 11 #include <linux/kernel.h> 12 #include <linux/socket.h> 13 #include <linux/netdevice.h> 14 #include <linux/skbuff.h> 15 #include <linux/printk.h> 16 17 #include <net/protocol.h> 18 #include <net/ipv6.h> 19 20 #include "ip6_offload.h" 21 22 static int ipv6_gso_pull_exthdrs(struct sk_buff *skb, int proto) 23 { 24 const struct net_offload *ops = NULL; 25 26 for (;;) { 27 struct ipv6_opt_hdr *opth; 28 int len; 29 30 if (proto != NEXTHDR_HOP) { 31 ops = rcu_dereference(inet6_offloads[proto]); 32 33 if (unlikely(!ops)) 34 break; 35 36 if (!(ops->flags & INET6_PROTO_GSO_EXTHDR)) 37 break; 38 } 39 40 if (unlikely(!pskb_may_pull(skb, 8))) 41 break; 42 43 opth = (void *)skb->data; 44 len = ipv6_optlen(opth); 45 46 if (unlikely(!pskb_may_pull(skb, len))) 47 break; 48 49 proto = opth->nexthdr; 50 __skb_pull(skb, len); 51 } 52 53 return proto; 54 } 55 56 static int ipv6_gso_send_check(struct sk_buff *skb) 57 { 58 const struct ipv6hdr *ipv6h; 59 const struct net_offload *ops; 60 int err = -EINVAL; 61 62 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 63 goto out; 64 65 ipv6h = ipv6_hdr(skb); 66 __skb_pull(skb, sizeof(*ipv6h)); 67 err = -EPROTONOSUPPORT; 68 69 ops = rcu_dereference(inet6_offloads[ 70 ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr)]); 71 72 if (likely(ops && ops->callbacks.gso_send_check)) { 73 skb_reset_transport_header(skb); 74 err = ops->callbacks.gso_send_check(skb); 75 } 76 77 out: 78 return err; 79 } 80 81 static struct sk_buff *ipv6_gso_segment(struct sk_buff *skb, 82 netdev_features_t features) 83 { 84 struct sk_buff *segs = ERR_PTR(-EINVAL); 85 struct ipv6hdr *ipv6h; 86 const struct net_offload *ops; 87 int proto; 88 struct frag_hdr *fptr; 89 unsigned int unfrag_ip6hlen; 90 u8 *prevhdr; 91 int offset = 0; 92 bool tunnel; 93 int nhoff; 94 95 if (unlikely(skb_shinfo(skb)->gso_type & 96 ~(SKB_GSO_UDP | 97 SKB_GSO_DODGY | 98 SKB_GSO_TCP_ECN | 99 SKB_GSO_GRE | 100 SKB_GSO_IPIP | 101 SKB_GSO_SIT | 102 SKB_GSO_UDP_TUNNEL | 103 SKB_GSO_MPLS | 104 SKB_GSO_TCPV6 | 105 0))) 106 goto out; 107 108 skb_reset_network_header(skb); 109 nhoff = skb_network_header(skb) - skb_mac_header(skb); 110 if (unlikely(!pskb_may_pull(skb, sizeof(*ipv6h)))) 111 goto out; 112 113 tunnel = SKB_GSO_CB(skb)->encap_level > 0; 114 if (tunnel) 115 features = skb->dev->hw_enc_features & netif_skb_features(skb); 116 SKB_GSO_CB(skb)->encap_level += sizeof(*ipv6h); 117 118 ipv6h = ipv6_hdr(skb); 119 __skb_pull(skb, sizeof(*ipv6h)); 120 segs = ERR_PTR(-EPROTONOSUPPORT); 121 122 proto = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr); 123 124 ops = rcu_dereference(inet6_offloads[proto]); 125 if (likely(ops && ops->callbacks.gso_segment)) { 126 skb_reset_transport_header(skb); 127 segs = ops->callbacks.gso_segment(skb, features); 128 } 129 130 if (IS_ERR(segs)) 131 goto out; 132 133 for (skb = segs; skb; skb = skb->next) { 134 ipv6h = (struct ipv6hdr *)(skb_mac_header(skb) + nhoff); 135 ipv6h->payload_len = htons(skb->len - nhoff - sizeof(*ipv6h)); 136 if (tunnel) { 137 skb_reset_inner_headers(skb); 138 skb->encapsulation = 1; 139 } 140 skb->network_header = (u8 *)ipv6h - skb->head; 141 142 if (!tunnel && proto == IPPROTO_UDP) { 143 unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr); 144 fptr = (struct frag_hdr *)((u8 *)ipv6h + unfrag_ip6hlen); 145 fptr->frag_off = htons(offset); 146 if (skb->next != NULL) 147 fptr->frag_off |= htons(IP6_MF); 148 offset += (ntohs(ipv6h->payload_len) - 149 sizeof(struct frag_hdr)); 150 } 151 } 152 153 out: 154 return segs; 155 } 156 157 /* Return the total length of all the extension hdrs, following the same 158 * logic in ipv6_gso_pull_exthdrs() when parsing ext-hdrs. 159 */ 160 static int ipv6_exthdrs_len(struct ipv6hdr *iph, 161 const struct net_offload **opps) 162 { 163 struct ipv6_opt_hdr *opth = (void *)iph; 164 int len = 0, proto, optlen = sizeof(*iph); 165 166 proto = iph->nexthdr; 167 for (;;) { 168 if (proto != NEXTHDR_HOP) { 169 *opps = rcu_dereference(inet6_offloads[proto]); 170 if (unlikely(!(*opps))) 171 break; 172 if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR)) 173 break; 174 } 175 opth = (void *)opth + optlen; 176 optlen = ipv6_optlen(opth); 177 len += optlen; 178 proto = opth->nexthdr; 179 } 180 return len; 181 } 182 183 static struct sk_buff **ipv6_gro_receive(struct sk_buff **head, 184 struct sk_buff *skb) 185 { 186 const struct net_offload *ops; 187 struct sk_buff **pp = NULL; 188 struct sk_buff *p; 189 struct ipv6hdr *iph; 190 unsigned int nlen; 191 unsigned int hlen; 192 unsigned int off; 193 u16 flush = 1; 194 int proto; 195 __wsum csum; 196 197 off = skb_gro_offset(skb); 198 hlen = off + sizeof(*iph); 199 iph = skb_gro_header_fast(skb, off); 200 if (skb_gro_header_hard(skb, hlen)) { 201 iph = skb_gro_header_slow(skb, hlen, off); 202 if (unlikely(!iph)) 203 goto out; 204 } 205 206 skb_set_network_header(skb, off); 207 skb_gro_pull(skb, sizeof(*iph)); 208 skb_set_transport_header(skb, skb_gro_offset(skb)); 209 210 flush += ntohs(iph->payload_len) != skb_gro_len(skb); 211 212 rcu_read_lock(); 213 proto = iph->nexthdr; 214 ops = rcu_dereference(inet6_offloads[proto]); 215 if (!ops || !ops->callbacks.gro_receive) { 216 __pskb_pull(skb, skb_gro_offset(skb)); 217 proto = ipv6_gso_pull_exthdrs(skb, proto); 218 skb_gro_pull(skb, -skb_transport_offset(skb)); 219 skb_reset_transport_header(skb); 220 __skb_push(skb, skb_gro_offset(skb)); 221 222 ops = rcu_dereference(inet6_offloads[proto]); 223 if (!ops || !ops->callbacks.gro_receive) 224 goto out_unlock; 225 226 iph = ipv6_hdr(skb); 227 } 228 229 NAPI_GRO_CB(skb)->proto = proto; 230 231 flush--; 232 nlen = skb_network_header_len(skb); 233 234 for (p = *head; p; p = p->next) { 235 const struct ipv6hdr *iph2; 236 __be32 first_word; /* <Version:4><Traffic_Class:8><Flow_Label:20> */ 237 238 if (!NAPI_GRO_CB(p)->same_flow) 239 continue; 240 241 iph2 = (struct ipv6hdr *)(p->data + off); 242 first_word = *(__be32 *)iph ^ *(__be32 *)iph2 ; 243 244 /* All fields must match except length and Traffic Class. 245 * XXX skbs on the gro_list have all been parsed and pulled 246 * already so we don't need to compare nlen 247 * (nlen != (sizeof(*iph2) + ipv6_exthdrs_len(iph2, &ops))) 248 * memcmp() alone below is suffcient, right? 249 */ 250 if ((first_word & htonl(0xF00FFFFF)) || 251 memcmp(&iph->nexthdr, &iph2->nexthdr, 252 nlen - offsetof(struct ipv6hdr, nexthdr))) { 253 NAPI_GRO_CB(p)->same_flow = 0; 254 continue; 255 } 256 /* flush if Traffic Class fields are different */ 257 NAPI_GRO_CB(p)->flush |= !!(first_word & htonl(0x0FF00000)); 258 NAPI_GRO_CB(p)->flush |= flush; 259 } 260 261 NAPI_GRO_CB(skb)->flush |= flush; 262 263 csum = skb->csum; 264 skb_postpull_rcsum(skb, iph, skb_network_header_len(skb)); 265 266 pp = ops->callbacks.gro_receive(head, skb); 267 268 skb->csum = csum; 269 270 out_unlock: 271 rcu_read_unlock(); 272 273 out: 274 NAPI_GRO_CB(skb)->flush |= flush; 275 276 return pp; 277 } 278 279 static int ipv6_gro_complete(struct sk_buff *skb, int nhoff) 280 { 281 const struct net_offload *ops; 282 struct ipv6hdr *iph = (struct ipv6hdr *)(skb->data + nhoff); 283 int err = -ENOSYS; 284 285 iph->payload_len = htons(skb->len - nhoff - sizeof(*iph)); 286 287 rcu_read_lock(); 288 289 nhoff += sizeof(*iph) + ipv6_exthdrs_len(iph, &ops); 290 if (WARN_ON(!ops || !ops->callbacks.gro_complete)) 291 goto out_unlock; 292 293 err = ops->callbacks.gro_complete(skb, nhoff); 294 295 out_unlock: 296 rcu_read_unlock(); 297 298 return err; 299 } 300 301 static struct packet_offload ipv6_packet_offload __read_mostly = { 302 .type = cpu_to_be16(ETH_P_IPV6), 303 .callbacks = { 304 .gso_send_check = ipv6_gso_send_check, 305 .gso_segment = ipv6_gso_segment, 306 .gro_receive = ipv6_gro_receive, 307 .gro_complete = ipv6_gro_complete, 308 }, 309 }; 310 311 static const struct net_offload sit_offload = { 312 .callbacks = { 313 .gso_send_check = ipv6_gso_send_check, 314 .gso_segment = ipv6_gso_segment, 315 }, 316 }; 317 318 static int __init ipv6_offload_init(void) 319 { 320 321 if (tcpv6_offload_init() < 0) 322 pr_crit("%s: Cannot add TCP protocol offload\n", __func__); 323 if (udp_offload_init() < 0) 324 pr_crit("%s: Cannot add UDP protocol offload\n", __func__); 325 if (ipv6_exthdrs_offload_init() < 0) 326 pr_crit("%s: Cannot add EXTHDRS protocol offload\n", __func__); 327 328 dev_add_offload(&ipv6_packet_offload); 329 330 inet_add_offload(&sit_offload, IPPROTO_IPV6); 331 332 return 0; 333 } 334 335 fs_initcall(ipv6_offload_init); 336