net/xfrm/xfrm_output.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * xfrm_output.c - Common IPsec encapsulation code.
   4  *
   5  * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
   6  */
   7
   8 #include <linux/errno.h>
   9 #include <linux/module.h>
  10 #include <linux/netdevice.h>
  11 #include <linux/netfilter.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/slab.h>
  14 #include <linux/spinlock.h>
  15 #include <net/dst.h>
  16 #include <net/gso.h>
  17 #include <net/icmp.h>
  18 #include <net/inet_ecn.h>
  19 #include <net/xfrm.h>
  20
  21 #if IS_ENABLED(CONFIG_IPV6)
  22 #include <net/ip6_route.h>
  23 #include <net/ipv6_stubs.h>
  24 #endif
  25
  26 #include "xfrm_inout.h"
  27
  28 static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb);
  29 static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb);
  30
  31 static int xfrm_skb_check_space(struct sk_buff *skb)
  32 {
  33         struct dst_entry *dst = skb_dst(skb);
  34         int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev)
  35                 - skb_headroom(skb);
  36         int ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
  37
  38         if (nhead <= 0) {
  39                 if (ntail <= 0)
  40                         return 0;
  41                 nhead = 0;
  42         } else if (ntail < 0)
  43                 ntail = 0;
  44
  45         return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
  46 }
  47
  48 /* Children define the path of the packet through the
  49  * Linux networking.  Thus, destinations are stackable.
  50  */
  51
  52 static struct dst_entry *skb_dst_pop(struct sk_buff *skb)
  53 {
  54         struct dst_entry *child = dst_clone(xfrm_dst_child(skb_dst(skb)));
  55
  56         skb_dst_drop(skb);
  57         return child;
  58 }
  59
  60 /* Add encapsulation header.
  61  *
  62  * The IP header will be moved forward to make space for the encapsulation
  63  * header.
  64  */
  65 static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
  66 {
  67         struct iphdr *iph = ip_hdr(skb);
  68         int ihl = iph->ihl * 4;
  69
  70         skb_set_inner_transport_header(skb, skb_transport_offset(skb));
  71
  72         skb_set_network_header(skb, -x->props.header_len);
  73         skb->mac_header = skb->network_header +
  74                           offsetof(struct iphdr, protocol);
  75         skb->transport_header = skb->network_header + ihl;
  76         __skb_pull(skb, ihl);
  77         memmove(skb_network_header(skb), iph, ihl);
  78         return 0;
  79 }
  80
  81 #if IS_ENABLED(CONFIG_IPV6_MIP6)
  82 static int mip6_rthdr_offset(struct sk_buff *skb, u8 **nexthdr, int type)
  83 {
  84         const unsigned char *nh = skb_network_header(skb);
  85         unsigned int offset = sizeof(struct ipv6hdr);
  86         unsigned int packet_len;
  87         int found_rhdr = 0;
  88
  89         packet_len = skb_tail_pointer(skb) - nh;
  90         *nexthdr = &ipv6_hdr(skb)->nexthdr;
  91
  92         while (offset <= packet_len) {
  93                 struct ipv6_opt_hdr *exthdr;
  94
  95                 switch (**nexthdr) {
  96                 case NEXTHDR_HOP:
  97                         break;
  98                 case NEXTHDR_ROUTING:
  99                         if (type == IPPROTO_ROUTING && offset + 3 <= packet_len) {
 100                                 struct ipv6_rt_hdr *rt;
 101
 102                                 rt = (struct ipv6_rt_hdr *)(nh + offset);
 103                                 if (rt->type != 0)
 104                                         return offset;
 105                         }
 106                         found_rhdr = 1;
 107                         break;
 108                 case NEXTHDR_DEST:
 109                         /* HAO MUST NOT appear more than once.
 110                          * XXX: It is better to try to find by the end of
 111                          * XXX: packet if HAO exists.
 112                          */
 113                         if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
 114                                 net_dbg_ratelimited("mip6: hao exists already, override\n");
 115                                 return offset;
 116                         }
 117
 118                         if (found_rhdr)
 119                                 return offset;
 120
 121                         break;
 122                 default:
 123                         return offset;
 124                 }
 125
 126                 if (offset + sizeof(struct ipv6_opt_hdr) > packet_len)
 127                         return -EINVAL;
 128
 129                 exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
 130                                                  offset);
 131                 offset += ipv6_optlen(exthdr);
 132                 if (offset > IPV6_MAXPLEN)
 133                         return -EINVAL;
 134                 *nexthdr = &exthdr->nexthdr;
 135         }
 136
 137         return -EINVAL;
 138 }
 139 #endif
 140
 141 #if IS_ENABLED(CONFIG_IPV6)
 142 static int xfrm6_hdr_offset(struct xfrm_state *x, struct sk_buff *skb, u8 **prevhdr)
 143 {
 144         switch (x->type->proto) {
 145 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 146         case IPPROTO_DSTOPTS:
 147         case IPPROTO_ROUTING:
 148                 return mip6_rthdr_offset(skb, prevhdr, x->type->proto);
 149 #endif
 150         default:
 151                 break;
 152         }
 153
 154         return ip6_find_1stfragopt(skb, prevhdr);
 155 }
 156 #endif
 157
 158 /* Add encapsulation header.
 159  *
 160  * The IP header and mutable extension headers will be moved forward to make
 161  * space for the encapsulation header.
 162  */
 163 static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb)
 164 {
 165 #if IS_ENABLED(CONFIG_IPV6)
 166         struct ipv6hdr *iph;
 167         u8 *prevhdr;
 168         int hdr_len;
 169
 170         iph = ipv6_hdr(skb);
 171         skb_set_inner_transport_header(skb, skb_transport_offset(skb));
 172
 173         hdr_len = xfrm6_hdr_offset(x, skb, &prevhdr);
 174         if (hdr_len < 0)
 175                 return hdr_len;
 176         skb_set_mac_header(skb,
 177                            (prevhdr - x->props.header_len) - skb->data);
 178         skb_set_network_header(skb, -x->props.header_len);
 179         skb->transport_header = skb->network_header + hdr_len;
 180         __skb_pull(skb, hdr_len);
 181         memmove(ipv6_hdr(skb), iph, hdr_len);
 182         return 0;
 183 #else
 184         WARN_ON_ONCE(1);
 185         return -EAFNOSUPPORT;
 186 #endif
 187 }
 188
 189 /* Add route optimization header space.
 190  *
 191  * The IP header and mutable extension headers will be moved forward to make
 192  * space for the route optimization header.
 193  */
 194 static int xfrm6_ro_output(struct xfrm_state *x, struct sk_buff *skb)
 195 {
 196 #if IS_ENABLED(CONFIG_IPV6)
 197         struct ipv6hdr *iph;
 198         u8 *prevhdr;
 199         int hdr_len;
 200
 201         iph = ipv6_hdr(skb);
 202
 203         hdr_len = xfrm6_hdr_offset(x, skb, &prevhdr);
 204         if (hdr_len < 0)
 205                 return hdr_len;
 206         skb_set_mac_header(skb,
 207                            (prevhdr - x->props.header_len) - skb->data);
 208         skb_set_network_header(skb, -x->props.header_len);
 209         skb->transport_header = skb->network_header + hdr_len;
 210         __skb_pull(skb, hdr_len);
 211         memmove(ipv6_hdr(skb), iph, hdr_len);
 212
 213         return 0;
 214 #else
 215         WARN_ON_ONCE(1);
 216         return -EAFNOSUPPORT;
 217 #endif
 218 }
 219
 220 /* Add encapsulation header.
 221  *
 222  * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
 223  */
 224 static int xfrm4_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb)
 225 {
 226         struct ip_beet_phdr *ph;
 227         struct iphdr *top_iph;
 228         int hdrlen, optlen;
 229
 230         hdrlen = 0;
 231         optlen = XFRM_MODE_SKB_CB(skb)->optlen;
 232         if (unlikely(optlen))
 233                 hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
 234
 235         skb_set_network_header(skb, -x->props.header_len - hdrlen +
 236                                (XFRM_MODE_SKB_CB(skb)->ihl - sizeof(*top_iph)));
 237         if (x->sel.family != AF_INET6)
 238                 skb->network_header += IPV4_BEET_PHMAXLEN;
 239         skb->mac_header = skb->network_header +
 240                           offsetof(struct iphdr, protocol);
 241         skb->transport_header = skb->network_header + sizeof(*top_iph);
 242
 243         xfrm4_beet_make_header(skb);
 244
 245         ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdrlen);
 246
 247         top_iph = ip_hdr(skb);
 248
 249         if (unlikely(optlen)) {
 250                 if (WARN_ON(optlen < 0))
 251                         return -EINVAL;
 252
 253                 ph->padlen = 4 - (optlen & 4);
 254                 ph->hdrlen = optlen / 8;
 255                 ph->nexthdr = top_iph->protocol;
 256                 if (ph->padlen)
 257                         memset(ph + 1, IPOPT_NOP, ph->padlen);
 258
 259                 top_iph->protocol = IPPROTO_BEETPH;
 260                 top_iph->ihl = sizeof(struct iphdr) / 4;
 261         }
 262
 263         top_iph->saddr = x->props.saddr.a4;
 264         top_iph->daddr = x->id.daddr.a4;
 265
 266         return 0;
 267 }
 268
 269 /* Add encapsulation header.
 270  *
 271  * The top IP header will be constructed per RFC 2401.
 272  */
 273 static int xfrm4_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb)
 274 {
 275         bool small_ipv6 = (skb->protocol == htons(ETH_P_IPV6)) && (skb->len <= IPV6_MIN_MTU);
 276         struct dst_entry *dst = skb_dst(skb);
 277         struct iphdr *top_iph;
 278         int flags;
 279
 280         skb_set_inner_network_header(skb, skb_network_offset(skb));
 281         skb_set_inner_transport_header(skb, skb_transport_offset(skb));
 282
 283         skb_set_network_header(skb, -x->props.header_len);
 284         skb->mac_header = skb->network_header +
 285                           offsetof(struct iphdr, protocol);
 286         skb->transport_header = skb->network_header + sizeof(*top_iph);
 287         top_iph = ip_hdr(skb);
 288
 289         top_iph->ihl = 5;
 290         top_iph->version = 4;
 291
 292         top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family);
 293
 294         /* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */
 295         if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
 296                 top_iph->tos = 0;
 297         else
 298                 top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
 299         top_iph->tos = INET_ECN_encapsulate(top_iph->tos,
 300                                             XFRM_MODE_SKB_CB(skb)->tos);
 301
 302         flags = x->props.flags;
 303         if (flags & XFRM_STATE_NOECN)
 304                 IP_ECN_clear(top_iph);
 305
 306         top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) || small_ipv6 ?
 307                 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
 308
 309         top_iph->ttl = ip4_dst_hoplimit(xfrm_dst_child(dst));
 310
 311         top_iph->saddr = x->props.saddr.a4;
 312         top_iph->daddr = x->id.daddr.a4;
 313         ip_select_ident(dev_net(dst->dev), skb, NULL);
 314
 315         return 0;
 316 }
 317
 318 #if IS_ENABLED(CONFIG_IPV6)
 319 static int xfrm6_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb)
 320 {
 321         struct dst_entry *dst = skb_dst(skb);
 322         struct ipv6hdr *top_iph;
 323         int dsfield;
 324
 325         skb_set_inner_network_header(skb, skb_network_offset(skb));
 326         skb_set_inner_transport_header(skb, skb_transport_offset(skb));
 327
 328         skb_set_network_header(skb, -x->props.header_len);
 329         skb->mac_header = skb->network_header +
 330                           offsetof(struct ipv6hdr, nexthdr);
 331         skb->transport_header = skb->network_header + sizeof(*top_iph);
 332         top_iph = ipv6_hdr(skb);
 333
 334         top_iph->version = 6;
 335
 336         memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
 337                sizeof(top_iph->flow_lbl));
 338         top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family);
 339
 340         if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
 341                 dsfield = 0;
 342         else
 343                 dsfield = XFRM_MODE_SKB_CB(skb)->tos;
 344         dsfield = INET_ECN_encapsulate(dsfield, XFRM_MODE_SKB_CB(skb)->tos);
 345         if (x->props.flags & XFRM_STATE_NOECN)
 346                 dsfield &= ~INET_ECN_MASK;
 347         ipv6_change_dsfield(top_iph, 0, dsfield);
 348         top_iph->hop_limit = ip6_dst_hoplimit(xfrm_dst_child(dst));
 349         top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
 350         top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
 351         return 0;
 352 }
 353
 354 static int xfrm6_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb)
 355 {
 356         struct ipv6hdr *top_iph;
 357         struct ip_beet_phdr *ph;
 358         int optlen, hdr_len;
 359
 360         hdr_len = 0;
 361         optlen = XFRM_MODE_SKB_CB(skb)->optlen;
 362         if (unlikely(optlen))
 363                 hdr_len += IPV4_BEET_PHMAXLEN - (optlen & 4);
 364
 365         skb_set_network_header(skb, -x->props.header_len - hdr_len);
 366         if (x->sel.family != AF_INET6)
 367                 skb->network_header += IPV4_BEET_PHMAXLEN;
 368         skb->mac_header = skb->network_header +
 369                           offsetof(struct ipv6hdr, nexthdr);
 370         skb->transport_header = skb->network_header + sizeof(*top_iph);
 371         ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdr_len);
 372
 373         xfrm6_beet_make_header(skb);
 374
 375         top_iph = ipv6_hdr(skb);
 376         if (unlikely(optlen)) {
 377                 if (WARN_ON(optlen < 0))
 378                         return -EINVAL;
 379
 380                 ph->padlen = 4 - (optlen & 4);
 381                 ph->hdrlen = optlen / 8;
 382                 ph->nexthdr = top_iph->nexthdr;
 383                 if (ph->padlen)
 384                         memset(ph + 1, IPOPT_NOP, ph->padlen);
 385
 386                 top_iph->nexthdr = IPPROTO_BEETPH;
 387         }
 388
 389         top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
 390         top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
 391         return 0;
 392 }
 393 #endif
 394
 395 /* Add encapsulation header.
 396  *
 397  * On exit, the transport header will be set to the start of the
 398  * encapsulation header to be filled in by x->type->output and the mac
 399  * header will be set to the nextheader (protocol for IPv4) field of the
 400  * extension header directly preceding the encapsulation header, or in
 401  * its absence, that of the top IP header.
 402  * The value of the network header will always point to the top IP header
 403  * while skb->data will point to the payload.
 404  */
 405 static int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
 406 {
 407         int err;
 408
 409         err = xfrm_inner_extract_output(x, skb);
 410         if (err)
 411                 return err;
 412
 413         IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
 414         skb->protocol = htons(ETH_P_IP);
 415
 416         switch (x->props.mode) {
 417         case XFRM_MODE_BEET:
 418                 return xfrm4_beet_encap_add(x, skb);
 419         case XFRM_MODE_TUNNEL:
 420                 return xfrm4_tunnel_encap_add(x, skb);
 421         }
 422
 423         WARN_ON_ONCE(1);
 424         return -EOPNOTSUPP;
 425 }
 426
 427 static int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
 428 {
 429 #if IS_ENABLED(CONFIG_IPV6)
 430         int err;
 431
 432         err = xfrm_inner_extract_output(x, skb);
 433         if (err)
 434                 return err;
 435
 436         skb->ignore_df = 1;
 437         skb->protocol = htons(ETH_P_IPV6);
 438
 439         switch (x->props.mode) {
 440         case XFRM_MODE_BEET:
 441                 return xfrm6_beet_encap_add(x, skb);
 442         case XFRM_MODE_TUNNEL:
 443                 return xfrm6_tunnel_encap_add(x, skb);
 444         default:
 445                 WARN_ON_ONCE(1);
 446                 return -EOPNOTSUPP;
 447         }
 448 #endif
 449         WARN_ON_ONCE(1);
 450         return -EAFNOSUPPORT;
 451 }
 452
 453 static int xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
 454 {
 455         switch (x->props.mode) {
 456         case XFRM_MODE_BEET:
 457         case XFRM_MODE_TUNNEL:
 458                 if (x->props.family == AF_INET)
 459                         return xfrm4_prepare_output(x, skb);
 460                 if (x->props.family == AF_INET6)
 461                         return xfrm6_prepare_output(x, skb);
 462                 break;
 463         case XFRM_MODE_TRANSPORT:
 464                 if (x->props.family == AF_INET)
 465                         return xfrm4_transport_output(x, skb);
 466                 if (x->props.family == AF_INET6)
 467                         return xfrm6_transport_output(x, skb);
 468                 break;
 469         case XFRM_MODE_ROUTEOPTIMIZATION:
 470                 if (x->props.family == AF_INET6)
 471                         return xfrm6_ro_output(x, skb);
 472                 WARN_ON_ONCE(1);
 473                 break;
 474         default:
 475                 WARN_ON_ONCE(1);
 476                 break;
 477         }
 478
 479         return -EOPNOTSUPP;
 480 }
 481
 482 #if IS_ENABLED(CONFIG_NET_PKTGEN)
 483 int pktgen_xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
 484 {
 485         return xfrm_outer_mode_output(x, skb);
 486 }
 487 EXPORT_SYMBOL_GPL(pktgen_xfrm_outer_mode_output);
 488 #endif
 489
 490 static int xfrm_output_one(struct sk_buff *skb, int err)
 491 {
 492         struct dst_entry *dst = skb_dst(skb);
 493         struct xfrm_state *x = dst->xfrm;
 494         struct net *net = xs_net(x);
 495
 496         if (err <= 0 || x->xso.type == XFRM_DEV_OFFLOAD_PACKET)
 497                 goto resume;
 498
 499         do {
 500                 err = xfrm_skb_check_space(skb);
 501                 if (err) {
 502                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
 503                         goto error_nolock;
 504                 }
 505
 506                 skb->mark = xfrm_smark_get(skb->mark, x);
 507
 508                 err = xfrm_outer_mode_output(x, skb);
 509                 if (err) {
 510                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
 511                         goto error_nolock;
 512                 }
 513
 514                 spin_lock_bh(&x->lock);
 515
 516                 if (unlikely(x->km.state != XFRM_STATE_VALID)) {
 517                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
 518                         err = -EINVAL;
 519                         goto error;
 520                 }
 521
 522                 err = xfrm_state_check_expire(x);
 523                 if (err) {
 524                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
 525                         goto error;
 526                 }
 527
 528                 err = xfrm_replay_overflow(x, skb);
 529                 if (err) {
 530                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
 531                         goto error;
 532                 }
 533
 534                 x->curlft.bytes += skb->len;
 535                 x->curlft.packets++;
 536                 x->lastused = ktime_get_real_seconds();
 537
 538                 spin_unlock_bh(&x->lock);
 539
 540                 skb_dst_force(skb);
 541                 if (!skb_dst(skb)) {
 542                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
 543                         err = -EHOSTUNREACH;
 544                         goto error_nolock;
 545                 }
 546
 547                 if (xfrm_offload(skb)) {
 548                         x->type_offload->encap(x, skb);
 549                 } else {
 550                         /* Inner headers are invalid now. */
 551                         skb->encapsulation = 0;
 552
 553                         err = x->type->output(x, skb);
 554                         if (err == -EINPROGRESS)
 555                                 goto out;
 556                 }
 557
 558 resume:
 559                 if (err) {
 560                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
 561                         goto error_nolock;
 562                 }
 563
 564                 dst = skb_dst_pop(skb);
 565                 if (!dst) {
 566                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
 567                         err = -EHOSTUNREACH;
 568                         goto error_nolock;
 569                 }
 570                 skb_dst_set(skb, dst);
 571                 x = dst->xfrm;
 572         } while (x && !(x->outer_mode.flags & XFRM_MODE_FLAG_TUNNEL));
 573
 574         return 0;
 575
 576 error:
 577         spin_unlock_bh(&x->lock);
 578 error_nolock:
 579         kfree_skb(skb);
 580 out:
 581         return err;
 582 }
 583
 584 int xfrm_output_resume(struct sock *sk, struct sk_buff *skb, int err)
 585 {
 586         struct net *net = xs_net(skb_dst(skb)->xfrm);
 587
 588         while (likely((err = xfrm_output_one(skb, err)) == 0)) {
 589                 nf_reset_ct(skb);
 590
 591                 err = skb_dst(skb)->ops->local_out(net, sk, skb);
 592                 if (unlikely(err != 1))
 593                         goto out;
 594
 595                 if (!skb_dst(skb)->xfrm)
 596                         return dst_output(net, sk, skb);
 597
 598                 err = nf_hook(skb_dst(skb)->ops->family,
 599                               NF_INET_POST_ROUTING, net, sk, skb,
 600                               NULL, skb_dst(skb)->dev, xfrm_output2);
 601                 if (unlikely(err != 1))
 602                         goto out;
 603         }
 604
 605         if (err == -EINPROGRESS)
 606                 err = 0;
 607
 608 out:
 609         return err;
 610 }
 611 EXPORT_SYMBOL_GPL(xfrm_output_resume);
 612
 613 static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
 614 {
 615         return xfrm_output_resume(sk, skb, 1);
 616 }
 617
 618 static int xfrm_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb)
 619 {
 620         struct sk_buff *segs, *nskb;
 621
 622         BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_GSO_CB_OFFSET);
 623         BUILD_BUG_ON(sizeof(*IP6CB(skb)) > SKB_GSO_CB_OFFSET);
 624         segs = skb_gso_segment(skb, 0);
 625         kfree_skb(skb);
 626         if (IS_ERR(segs))
 627                 return PTR_ERR(segs);
 628         if (segs == NULL)
 629                 return -EINVAL;
 630
 631         skb_list_walk_safe(segs, segs, nskb) {
 632                 int err;
 633
 634                 skb_mark_not_on_list(segs);
 635                 err = xfrm_output2(net, sk, segs);
 636
 637                 if (unlikely(err)) {
 638                         kfree_skb_list(nskb);
 639                         return err;
 640                 }
 641         }
 642
 643         return 0;
 644 }
 645
 646 /* For partial checksum offload, the outer header checksum is calculated
 647  * by software and the inner header checksum is calculated by hardware.
 648  * This requires hardware to know the inner packet type to calculate
 649  * the inner header checksum. Save inner ip protocol here to avoid
 650  * traversing the packet in the vendor's xmit code.
 651  * For IPsec tunnel mode save the ip protocol from the IP header of the
 652  * plain text packet. Otherwise If the encap type is IPIP, just save
 653  * skb->inner_ipproto in any other case get the ip protocol from the IP
 654  * header.
 655  */
 656 static void xfrm_get_inner_ipproto(struct sk_buff *skb, struct xfrm_state *x)
 657 {
 658         struct xfrm_offload *xo = xfrm_offload(skb);
 659         const struct ethhdr *eth;
 660
 661         if (!xo)
 662                 return;
 663
 664         if (x->outer_mode.encap == XFRM_MODE_TUNNEL) {
 665                 switch (x->outer_mode.family) {
 666                 case AF_INET:
 667                         xo->inner_ipproto = ip_hdr(skb)->protocol;
 668                         break;
 669                 case AF_INET6:
 670                         xo->inner_ipproto = ipv6_hdr(skb)->nexthdr;
 671                         break;
 672                 default:
 673                         break;
 674                 }
 675
 676                 return;
 677         }
 678
 679         /* non-Tunnel Mode */
 680         if (!skb->encapsulation)
 681                 return;
 682
 683         if (skb->inner_protocol_type == ENCAP_TYPE_IPPROTO) {
 684                 xo->inner_ipproto = skb->inner_ipproto;
 685                 return;
 686         }
 687
 688         if (skb->inner_protocol_type != ENCAP_TYPE_ETHER)
 689                 return;
 690
 691         eth = (struct ethhdr *)skb_inner_mac_header(skb);
 692
 693         switch (ntohs(eth->h_proto)) {
 694         case ETH_P_IPV6:
 695                 xo->inner_ipproto = inner_ipv6_hdr(skb)->nexthdr;
 696                 break;
 697         case ETH_P_IP:
 698                 xo->inner_ipproto = inner_ip_hdr(skb)->protocol;
 699                 break;
 700         }
 701 }
 702
 703 int xfrm_output(struct sock *sk, struct sk_buff *skb)
 704 {
 705         struct net *net = dev_net(skb_dst(skb)->dev);
 706         struct xfrm_state *x = skb_dst(skb)->xfrm;
 707         int family;
 708         int err;
 709
 710         family = (x->xso.type != XFRM_DEV_OFFLOAD_PACKET) ? x->outer_mode.family
 711                 : skb_dst(skb)->ops->family;
 712
 713         switch (family) {
 714         case AF_INET:
 715                 memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 716                 IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
 717                 break;
 718         case AF_INET6:
 719                 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
 720
 721                 IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
 722                 break;
 723         }
 724
 725         if (x->xso.type == XFRM_DEV_OFFLOAD_PACKET) {
 726                 if (!xfrm_dev_offload_ok(skb, x)) {
 727                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
 728                         kfree_skb(skb);
 729                         return -EHOSTUNREACH;
 730                 }
 731
 732                 return xfrm_output_resume(sk, skb, 0);
 733         }
 734
 735         secpath_reset(skb);
 736
 737         if (xfrm_dev_offload_ok(skb, x)) {
 738                 struct sec_path *sp;
 739
 740                 sp = secpath_set(skb);
 741                 if (!sp) {
 742                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
 743                         kfree_skb(skb);
 744                         return -ENOMEM;
 745                 }
 746
 747                 sp->olen++;
 748                 sp->xvec[sp->len++] = x;
 749                 xfrm_state_hold(x);
 750
 751                 xfrm_get_inner_ipproto(skb, x);
 752                 skb->encapsulation = 1;
 753
 754                 if (skb_is_gso(skb)) {
 755                         if (skb->inner_protocol)
 756                                 return xfrm_output_gso(net, sk, skb);
 757
 758                         skb_shinfo(skb)->gso_type |= SKB_GSO_ESP;
 759                         goto out;
 760                 }
 761
 762                 if (x->xso.dev && x->xso.dev->features & NETIF_F_HW_ESP_TX_CSUM)
 763                         goto out;
 764         } else {
 765                 if (skb_is_gso(skb))
 766                         return xfrm_output_gso(net, sk, skb);
 767         }
 768
 769         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 770                 err = skb_checksum_help(skb);
 771                 if (err) {
 772                         XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
 773                         kfree_skb(skb);
 774                         return err;
 775                 }
 776         }
 777
 778 out:
 779         return xfrm_output2(net, sk, skb);
 780 }
 781 EXPORT_SYMBOL_GPL(xfrm_output);
 782
 783 static int xfrm4_tunnel_check_size(struct sk_buff *skb)
 784 {
 785         int mtu, ret = 0;
 786
 787         if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
 788                 goto out;
 789
 790         if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
 791                 goto out;
 792
 793         mtu = dst_mtu(skb_dst(skb));
 794         if ((!skb_is_gso(skb) && skb->len > mtu) ||
 795             (skb_is_gso(skb) &&
 796              !skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) {
 797                 skb->protocol = htons(ETH_P_IP);
 798
 799                 if (skb->sk)
 800                         xfrm_local_error(skb, mtu);
 801                 else
 802                         icmp_send(skb, ICMP_DEST_UNREACH,
 803                                   ICMP_FRAG_NEEDED, htonl(mtu));
 804                 ret = -EMSGSIZE;
 805         }
 806 out:
 807         return ret;
 808 }
 809
 810 static int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
 811 {
 812         int err;
 813
 814         if (x->outer_mode.encap == XFRM_MODE_BEET &&
 815             ip_is_fragment(ip_hdr(skb))) {
 816                 net_warn_ratelimited("BEET mode doesn't support inner IPv4 fragments\n");
 817                 return -EAFNOSUPPORT;
 818         }
 819
 820         err = xfrm4_tunnel_check_size(skb);
 821         if (err)
 822                 return err;
 823
 824         XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
 825
 826         xfrm4_extract_header(skb);
 827         return 0;
 828 }
 829
 830 #if IS_ENABLED(CONFIG_IPV6)
 831 static int xfrm6_tunnel_check_size(struct sk_buff *skb)
 832 {
 833         int mtu, ret = 0;
 834         struct dst_entry *dst = skb_dst(skb);
 835
 836         if (skb->ignore_df)
 837                 goto out;
 838
 839         mtu = dst_mtu(dst);
 840         if (mtu < IPV6_MIN_MTU)
 841                 mtu = IPV6_MIN_MTU;
 842
 843         if ((!skb_is_gso(skb) && skb->len > mtu) ||
 844             (skb_is_gso(skb) &&
 845              !skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) {
 846                 skb->dev = dst->dev;
 847                 skb->protocol = htons(ETH_P_IPV6);
 848
 849                 if (xfrm6_local_dontfrag(skb->sk))
 850                         ipv6_stub->xfrm6_local_rxpmtu(skb, mtu);
 851                 else if (skb->sk)
 852                         xfrm_local_error(skb, mtu);
 853                 else
 854                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 855                 ret = -EMSGSIZE;
 856         }
 857 out:
 858         return ret;
 859 }
 860 #endif
 861
 862 static int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
 863 {
 864 #if IS_ENABLED(CONFIG_IPV6)
 865         int err;
 866
 867         err = xfrm6_tunnel_check_size(skb);
 868         if (err)
 869                 return err;
 870
 871         XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
 872
 873         xfrm6_extract_header(skb);
 874         return 0;
 875 #else
 876         WARN_ON_ONCE(1);
 877         return -EAFNOSUPPORT;
 878 #endif
 879 }
 880
 881 static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
 882 {
 883         switch (skb->protocol) {
 884         case htons(ETH_P_IP):
 885                 return xfrm4_extract_output(x, skb);
 886         case htons(ETH_P_IPV6):
 887                 return xfrm6_extract_output(x, skb);
 888         }
 889
 890         return -EAFNOSUPPORT;
 891 }
 892
 893 void xfrm_local_error(struct sk_buff *skb, int mtu)
 894 {
 895         unsigned int proto;
 896         struct xfrm_state_afinfo *afinfo;
 897
 898         if (skb->protocol == htons(ETH_P_IP))
 899                 proto = AF_INET;
 900         else if (skb->protocol == htons(ETH_P_IPV6) &&
 901                  skb->sk->sk_family == AF_INET6)
 902                 proto = AF_INET6;
 903         else
 904                 return;
 905
 906         afinfo = xfrm_state_get_afinfo(proto);
 907         if (afinfo) {
 908                 afinfo->local_error(skb, mtu);
 909                 rcu_read_unlock();
 910         }
 911 }
 912 EXPORT_SYMBOL_GPL(xfrm_local_error);