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 struct sk_buff *__skb_udp_tunnel_segment(struct sk_buff *skb, 18 netdev_features_t features, 19 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb, 20 netdev_features_t features), 21 __be16 new_protocol, bool is_ipv6) 22 { 23 int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb); 24 bool remcsum, need_csum, offload_csum, ufo; 25 struct sk_buff *segs = ERR_PTR(-EINVAL); 26 struct udphdr *uh = udp_hdr(skb); 27 u16 mac_offset = skb->mac_header; 28 __be16 protocol = skb->protocol; 29 u16 mac_len = skb->mac_len; 30 int udp_offset, outer_hlen; 31 __wsum partial; 32 33 if (unlikely(!pskb_may_pull(skb, tnl_hlen))) 34 goto out; 35 36 /* Adjust partial header checksum to negate old length. 37 * We cannot rely on the value contained in uh->len as it is 38 * possible that the actual value exceeds the boundaries of the 39 * 16 bit length field due to the header being added outside of an 40 * IP or IPv6 frame that was already limited to 64K - 1. 41 */ 42 partial = csum_sub(csum_unfold(uh->check), 43 (__force __wsum)htonl(skb->len)); 44 45 /* setup inner skb. */ 46 skb->encapsulation = 0; 47 SKB_GSO_CB(skb)->encap_level = 0; 48 __skb_pull(skb, tnl_hlen); 49 skb_reset_mac_header(skb); 50 skb_set_network_header(skb, skb_inner_network_offset(skb)); 51 skb->mac_len = skb_inner_network_offset(skb); 52 skb->protocol = new_protocol; 53 54 need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM); 55 skb->encap_hdr_csum = need_csum; 56 57 remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM); 58 skb->remcsum_offload = remcsum; 59 60 ufo = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP); 61 62 /* Try to offload checksum if possible */ 63 offload_csum = !!(need_csum && 64 (skb->dev->features & 65 (is_ipv6 ? (NETIF_F_HW_CSUM | NETIF_F_IPV6_CSUM) : 66 (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM)))); 67 68 features &= skb->dev->hw_enc_features; 69 70 /* The only checksum offload we care about from here on out is the 71 * outer one so strip the existing checksum feature flags and 72 * instead set the flag based on our outer checksum offload value. 73 */ 74 if (remcsum || ufo) { 75 features &= ~NETIF_F_CSUM_MASK; 76 if (!need_csum || offload_csum) 77 features |= NETIF_F_HW_CSUM; 78 } 79 80 /* segment inner packet. */ 81 segs = gso_inner_segment(skb, features); 82 if (IS_ERR_OR_NULL(segs)) { 83 skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset, 84 mac_len); 85 goto out; 86 } 87 88 outer_hlen = skb_tnl_header_len(skb); 89 udp_offset = outer_hlen - tnl_hlen; 90 skb = segs; 91 do { 92 __be16 len; 93 94 if (remcsum) 95 skb->ip_summed = CHECKSUM_NONE; 96 97 /* Set up inner headers if we are offloading inner checksum */ 98 if (skb->ip_summed == CHECKSUM_PARTIAL) { 99 skb_reset_inner_headers(skb); 100 skb->encapsulation = 1; 101 } 102 103 skb->mac_len = mac_len; 104 skb->protocol = protocol; 105 106 __skb_push(skb, outer_hlen); 107 skb_reset_mac_header(skb); 108 skb_set_network_header(skb, mac_len); 109 skb_set_transport_header(skb, udp_offset); 110 len = htons(skb->len - udp_offset); 111 uh = udp_hdr(skb); 112 uh->len = len; 113 114 if (!need_csum) 115 continue; 116 117 uh->check = ~csum_fold(csum_add(partial, (__force __wsum)len)); 118 119 if (skb->encapsulation || !offload_csum) { 120 uh->check = gso_make_checksum(skb, ~uh->check); 121 if (uh->check == 0) 122 uh->check = CSUM_MANGLED_0; 123 } else { 124 skb->ip_summed = CHECKSUM_PARTIAL; 125 skb->csum_start = skb_transport_header(skb) - skb->head; 126 skb->csum_offset = offsetof(struct udphdr, check); 127 } 128 } while ((skb = skb->next)); 129 out: 130 return segs; 131 } 132 133 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, 134 netdev_features_t features, 135 bool is_ipv6) 136 { 137 __be16 protocol = skb->protocol; 138 const struct net_offload **offloads; 139 const struct net_offload *ops; 140 struct sk_buff *segs = ERR_PTR(-EINVAL); 141 struct sk_buff *(*gso_inner_segment)(struct sk_buff *skb, 142 netdev_features_t features); 143 144 rcu_read_lock(); 145 146 switch (skb->inner_protocol_type) { 147 case ENCAP_TYPE_ETHER: 148 protocol = skb->inner_protocol; 149 gso_inner_segment = skb_mac_gso_segment; 150 break; 151 case ENCAP_TYPE_IPPROTO: 152 offloads = is_ipv6 ? inet6_offloads : inet_offloads; 153 ops = rcu_dereference(offloads[skb->inner_ipproto]); 154 if (!ops || !ops->callbacks.gso_segment) 155 goto out_unlock; 156 gso_inner_segment = ops->callbacks.gso_segment; 157 break; 158 default: 159 goto out_unlock; 160 } 161 162 segs = __skb_udp_tunnel_segment(skb, features, gso_inner_segment, 163 protocol, is_ipv6); 164 165 out_unlock: 166 rcu_read_unlock(); 167 168 return segs; 169 } 170 EXPORT_SYMBOL(skb_udp_tunnel_segment); 171 172 static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, 173 netdev_features_t features) 174 { 175 struct sk_buff *segs = ERR_PTR(-EINVAL); 176 unsigned int mss; 177 __wsum csum; 178 struct udphdr *uh; 179 struct iphdr *iph; 180 181 if (skb->encapsulation && 182 (skb_shinfo(skb)->gso_type & 183 (SKB_GSO_UDP_TUNNEL|SKB_GSO_UDP_TUNNEL_CSUM))) { 184 segs = skb_udp_tunnel_segment(skb, features, false); 185 goto out; 186 } 187 188 if (!pskb_may_pull(skb, sizeof(struct udphdr))) 189 goto out; 190 191 mss = skb_shinfo(skb)->gso_size; 192 if (unlikely(skb->len <= mss)) 193 goto out; 194 195 if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) { 196 /* Packet is from an untrusted source, reset gso_segs. */ 197 int type = skb_shinfo(skb)->gso_type; 198 199 if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY | 200 SKB_GSO_UDP_TUNNEL | 201 SKB_GSO_UDP_TUNNEL_CSUM | 202 SKB_GSO_TUNNEL_REMCSUM | 203 SKB_GSO_IPIP | 204 SKB_GSO_GRE | SKB_GSO_GRE_CSUM) || 205 !(type & (SKB_GSO_UDP)))) 206 goto out; 207 208 skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss); 209 210 segs = NULL; 211 goto out; 212 } 213 214 /* Do software UFO. Complete and fill in the UDP checksum as 215 * HW cannot do checksum of UDP packets sent as multiple 216 * IP fragments. 217 */ 218 219 uh = udp_hdr(skb); 220 iph = ip_hdr(skb); 221 222 uh->check = 0; 223 csum = skb_checksum(skb, 0, skb->len, 0); 224 uh->check = udp_v4_check(skb->len, iph->saddr, iph->daddr, csum); 225 if (uh->check == 0) 226 uh->check = CSUM_MANGLED_0; 227 228 skb->ip_summed = CHECKSUM_NONE; 229 230 /* If there is no outer header we can fake a checksum offload 231 * due to the fact that we have already done the checksum in 232 * software prior to segmenting the frame. 233 */ 234 if (!skb->encap_hdr_csum) 235 features |= NETIF_F_HW_CSUM; 236 237 /* Fragment the skb. IP headers of the fragments are updated in 238 * inet_gso_segment() 239 */ 240 segs = skb_segment(skb, features); 241 out: 242 return segs; 243 } 244 245 struct sk_buff **udp_gro_receive(struct sk_buff **head, struct sk_buff *skb, 246 struct udphdr *uh, udp_lookup_t lookup) 247 { 248 struct sk_buff *p, **pp = NULL; 249 struct udphdr *uh2; 250 unsigned int off = skb_gro_offset(skb); 251 int flush = 1; 252 struct sock *sk; 253 254 if (NAPI_GRO_CB(skb)->encap_mark || 255 (skb->ip_summed != CHECKSUM_PARTIAL && 256 NAPI_GRO_CB(skb)->csum_cnt == 0 && 257 !NAPI_GRO_CB(skb)->csum_valid)) 258 goto out; 259 260 /* mark that this skb passed once through the tunnel gro layer */ 261 NAPI_GRO_CB(skb)->encap_mark = 1; 262 263 rcu_read_lock(); 264 sk = (*lookup)(skb, uh->source, uh->dest); 265 266 if (sk && udp_sk(sk)->gro_receive) 267 goto unflush; 268 goto out_unlock; 269 270 unflush: 271 flush = 0; 272 273 for (p = *head; p; p = p->next) { 274 if (!NAPI_GRO_CB(p)->same_flow) 275 continue; 276 277 uh2 = (struct udphdr *)(p->data + off); 278 279 /* Match ports and either checksums are either both zero 280 * or nonzero. 281 */ 282 if ((*(u32 *)&uh->source != *(u32 *)&uh2->source) || 283 (!uh->check ^ !uh2->check)) { 284 NAPI_GRO_CB(p)->same_flow = 0; 285 continue; 286 } 287 } 288 289 skb_gro_pull(skb, sizeof(struct udphdr)); /* pull encapsulating udp header */ 290 skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr)); 291 pp = udp_sk(sk)->gro_receive(sk, head, skb); 292 293 out_unlock: 294 rcu_read_unlock(); 295 out: 296 NAPI_GRO_CB(skb)->flush |= flush; 297 return pp; 298 } 299 EXPORT_SYMBOL(udp_gro_receive); 300 301 static struct sk_buff **udp4_gro_receive(struct sk_buff **head, 302 struct sk_buff *skb) 303 { 304 struct udphdr *uh = udp_gro_udphdr(skb); 305 306 if (unlikely(!uh)) 307 goto flush; 308 309 /* Don't bother verifying checksum if we're going to flush anyway. */ 310 if (NAPI_GRO_CB(skb)->flush) 311 goto skip; 312 313 if (skb_gro_checksum_validate_zero_check(skb, IPPROTO_UDP, uh->check, 314 inet_gro_compute_pseudo)) 315 goto flush; 316 else if (uh->check) 317 skb_gro_checksum_try_convert(skb, IPPROTO_UDP, uh->check, 318 inet_gro_compute_pseudo); 319 skip: 320 NAPI_GRO_CB(skb)->is_ipv6 = 0; 321 return udp_gro_receive(head, skb, uh, udp4_lib_lookup_skb); 322 323 flush: 324 NAPI_GRO_CB(skb)->flush = 1; 325 return NULL; 326 } 327 328 int udp_gro_complete(struct sk_buff *skb, int nhoff, 329 udp_lookup_t lookup) 330 { 331 __be16 newlen = htons(skb->len - nhoff); 332 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); 333 int err = -ENOSYS; 334 struct sock *sk; 335 336 uh->len = newlen; 337 338 rcu_read_lock(); 339 sk = (*lookup)(skb, uh->source, uh->dest); 340 if (sk && udp_sk(sk)->gro_complete) 341 err = udp_sk(sk)->gro_complete(sk, skb, 342 nhoff + sizeof(struct udphdr)); 343 rcu_read_unlock(); 344 345 if (skb->remcsum_offload) 346 skb_shinfo(skb)->gso_type |= SKB_GSO_TUNNEL_REMCSUM; 347 348 skb->encapsulation = 1; 349 skb_set_inner_mac_header(skb, nhoff + sizeof(struct udphdr)); 350 351 return err; 352 } 353 EXPORT_SYMBOL(udp_gro_complete); 354 355 static int udp4_gro_complete(struct sk_buff *skb, int nhoff) 356 { 357 const struct iphdr *iph = ip_hdr(skb); 358 struct udphdr *uh = (struct udphdr *)(skb->data + nhoff); 359 360 if (uh->check) { 361 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM; 362 uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr, 363 iph->daddr, 0); 364 } else { 365 skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL; 366 } 367 368 return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb); 369 } 370 371 static const struct net_offload udpv4_offload = { 372 .callbacks = { 373 .gso_segment = udp4_ufo_fragment, 374 .gro_receive = udp4_gro_receive, 375 .gro_complete = udp4_gro_complete, 376 }, 377 }; 378 379 int __init udpv4_offload_init(void) 380 { 381 return inet_add_offload(&udpv4_offload, IPPROTO_UDP); 382 } 383