diff options
Diffstat (limited to '')
| -rw-r--r-- | net/xfrm/xfrm_output.c | 909 |
1 files changed, 909 insertions, 0 deletions
diff --git a/net/xfrm/xfrm_output.c b/net/xfrm/xfrm_output.c new file mode 100644 index 000000000..9a5e79a38 --- /dev/null +++ b/net/xfrm/xfrm_output.c @@ -0,0 +1,909 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * xfrm_output.c - Common IPsec encapsulation code. + * + * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au> + */ + +#include <linux/errno.h> +#include <linux/module.h> +#include <linux/netdevice.h> +#include <linux/netfilter.h> +#include <linux/skbuff.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <net/dst.h> +#include <net/icmp.h> +#include <net/inet_ecn.h> +#include <net/xfrm.h> + +#if IS_ENABLED(CONFIG_IPV6) +#include <net/ip6_route.h> +#include <net/ipv6_stubs.h> +#endif + +#include "xfrm_inout.h" + +static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb); +static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb); + +static int xfrm_skb_check_space(struct sk_buff *skb) +{ + struct dst_entry *dst = skb_dst(skb); + int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev) + - skb_headroom(skb); + int ntail = dst->dev->needed_tailroom - skb_tailroom(skb); + + if (nhead <= 0) { + if (ntail <= 0) + return 0; + nhead = 0; + } else if (ntail < 0) + ntail = 0; + + return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC); +} + +/* Children define the path of the packet through the + * Linux networking. Thus, destinations are stackable. + */ + +static struct dst_entry *skb_dst_pop(struct sk_buff *skb) +{ + struct dst_entry *child = dst_clone(xfrm_dst_child(skb_dst(skb))); + + skb_dst_drop(skb); + return child; +} + +/* Add encapsulation header. + * + * The IP header will be moved forward to make space for the encapsulation + * header. + */ +static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb) +{ + struct iphdr *iph = ip_hdr(skb); + int ihl = iph->ihl * 4; + + skb_set_inner_transport_header(skb, skb_transport_offset(skb)); + + skb_set_network_header(skb, -x->props.header_len); + skb->mac_header = skb->network_header + + offsetof(struct iphdr, protocol); + skb->transport_header = skb->network_header + ihl; + __skb_pull(skb, ihl); + memmove(skb_network_header(skb), iph, ihl); + return 0; +} + +#if IS_ENABLED(CONFIG_IPV6_MIP6) +static int mip6_rthdr_offset(struct sk_buff *skb, u8 **nexthdr, int type) +{ + const unsigned char *nh = skb_network_header(skb); + unsigned int offset = sizeof(struct ipv6hdr); + unsigned int packet_len; + int found_rhdr = 0; + + packet_len = skb_tail_pointer(skb) - nh; + *nexthdr = &ipv6_hdr(skb)->nexthdr; + + while (offset <= packet_len) { + struct ipv6_opt_hdr *exthdr; + + switch (**nexthdr) { + case NEXTHDR_HOP: + break; + case NEXTHDR_ROUTING: + if (type == IPPROTO_ROUTING && offset + 3 <= packet_len) { + struct ipv6_rt_hdr *rt; + + rt = (struct ipv6_rt_hdr *)(nh + offset); + if (rt->type != 0) + return offset; + } + found_rhdr = 1; + break; + case NEXTHDR_DEST: + /* HAO MUST NOT appear more than once. + * XXX: It is better to try to find by the end of + * XXX: packet if HAO exists. + */ + if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) { + net_dbg_ratelimited("mip6: hao exists already, override\n"); + return offset; + } + + if (found_rhdr) + return offset; + + break; + default: + return offset; + } + + if (offset + sizeof(struct ipv6_opt_hdr) > packet_len) + return -EINVAL; + + exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) + + offset); + offset += ipv6_optlen(exthdr); + if (offset > IPV6_MAXPLEN) + return -EINVAL; + *nexthdr = &exthdr->nexthdr; + } + + return -EINVAL; +} +#endif + +#if IS_ENABLED(CONFIG_IPV6) +static int xfrm6_hdr_offset(struct xfrm_state *x, struct sk_buff *skb, u8 **prevhdr) +{ + switch (x->type->proto) { +#if IS_ENABLED(CONFIG_IPV6_MIP6) + case IPPROTO_DSTOPTS: + case IPPROTO_ROUTING: + return mip6_rthdr_offset(skb, prevhdr, x->type->proto); +#endif + default: + break; + } + + return ip6_find_1stfragopt(skb, prevhdr); +} +#endif + +/* Add encapsulation header. + * + * The IP header and mutable extension headers will be moved forward to make + * space for the encapsulation header. + */ +static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb) +{ +#if IS_ENABLED(CONFIG_IPV6) + struct ipv6hdr *iph; + u8 *prevhdr; + int hdr_len; + + iph = ipv6_hdr(skb); + skb_set_inner_transport_header(skb, skb_transport_offset(skb)); + + hdr_len = xfrm6_hdr_offset(x, skb, &prevhdr); + if (hdr_len < 0) + return hdr_len; + skb_set_mac_header(skb, + (prevhdr - x->props.header_len) - skb->data); + skb_set_network_header(skb, -x->props.header_len); + skb->transport_header = skb->network_header + hdr_len; + __skb_pull(skb, hdr_len); + memmove(ipv6_hdr(skb), iph, hdr_len); + return 0; +#else + WARN_ON_ONCE(1); + return -EAFNOSUPPORT; +#endif +} + +/* Add route optimization header space. + * + * The IP header and mutable extension headers will be moved forward to make + * space for the route optimization header. + */ +static int xfrm6_ro_output(struct xfrm_state *x, struct sk_buff *skb) +{ +#if IS_ENABLED(CONFIG_IPV6) + struct ipv6hdr *iph; + u8 *prevhdr; + int hdr_len; + + iph = ipv6_hdr(skb); + + hdr_len = xfrm6_hdr_offset(x, skb, &prevhdr); + if (hdr_len < 0) + return hdr_len; + skb_set_mac_header(skb, + (prevhdr - x->props.header_len) - skb->data); + skb_set_network_header(skb, -x->props.header_len); + skb->transport_header = skb->network_header + hdr_len; + __skb_pull(skb, hdr_len); + memmove(ipv6_hdr(skb), iph, hdr_len); + + x->lastused = ktime_get_real_seconds(); + + return 0; +#else + WARN_ON_ONCE(1); + return -EAFNOSUPPORT; +#endif +} + +/* Add encapsulation header. + * + * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt. + */ +static int xfrm4_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb) +{ + struct ip_beet_phdr *ph; + struct iphdr *top_iph; + int hdrlen, optlen; + + hdrlen = 0; + optlen = XFRM_MODE_SKB_CB(skb)->optlen; + if (unlikely(optlen)) + hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4); + + skb_set_network_header(skb, -x->props.header_len - hdrlen + + (XFRM_MODE_SKB_CB(skb)->ihl - sizeof(*top_iph))); + if (x->sel.family != AF_INET6) + skb->network_header += IPV4_BEET_PHMAXLEN; + skb->mac_header = skb->network_header + + offsetof(struct iphdr, protocol); + skb->transport_header = skb->network_header + sizeof(*top_iph); + + xfrm4_beet_make_header(skb); + + ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdrlen); + + top_iph = ip_hdr(skb); + + if (unlikely(optlen)) { + if (WARN_ON(optlen < 0)) + return -EINVAL; + + ph->padlen = 4 - (optlen & 4); + ph->hdrlen = optlen / 8; + ph->nexthdr = top_iph->protocol; + if (ph->padlen) + memset(ph + 1, IPOPT_NOP, ph->padlen); + + top_iph->protocol = IPPROTO_BEETPH; + top_iph->ihl = sizeof(struct iphdr) / 4; + } + + top_iph->saddr = x->props.saddr.a4; + top_iph->daddr = x->id.daddr.a4; + + return 0; +} + +/* Add encapsulation header. + * + * The top IP header will be constructed per RFC 2401. + */ +static int xfrm4_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb) +{ + bool small_ipv6 = (skb->protocol == htons(ETH_P_IPV6)) && (skb->len <= IPV6_MIN_MTU); + struct dst_entry *dst = skb_dst(skb); + struct iphdr *top_iph; + int flags; + + skb_set_inner_network_header(skb, skb_network_offset(skb)); + skb_set_inner_transport_header(skb, skb_transport_offset(skb)); + + skb_set_network_header(skb, -x->props.header_len); + skb->mac_header = skb->network_header + + offsetof(struct iphdr, protocol); + skb->transport_header = skb->network_header + sizeof(*top_iph); + top_iph = ip_hdr(skb); + + top_iph->ihl = 5; + top_iph->version = 4; + + top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family); + + /* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */ + if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP) + top_iph->tos = 0; + else + top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos; + top_iph->tos = INET_ECN_encapsulate(top_iph->tos, + XFRM_MODE_SKB_CB(skb)->tos); + + flags = x->props.flags; + if (flags & XFRM_STATE_NOECN) + IP_ECN_clear(top_iph); + + top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) || small_ipv6 ? + 0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF)); + + top_iph->ttl = ip4_dst_hoplimit(xfrm_dst_child(dst)); + + top_iph->saddr = x->props.saddr.a4; + top_iph->daddr = x->id.daddr.a4; + ip_select_ident(dev_net(dst->dev), skb, NULL); + + return 0; +} + +#if IS_ENABLED(CONFIG_IPV6) +static int xfrm6_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb) +{ + struct dst_entry *dst = skb_dst(skb); + struct ipv6hdr *top_iph; + int dsfield; + + skb_set_inner_network_header(skb, skb_network_offset(skb)); + skb_set_inner_transport_header(skb, skb_transport_offset(skb)); + + skb_set_network_header(skb, -x->props.header_len); + skb->mac_header = skb->network_header + + offsetof(struct ipv6hdr, nexthdr); + skb->transport_header = skb->network_header + sizeof(*top_iph); + top_iph = ipv6_hdr(skb); + + top_iph->version = 6; + + memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl, + sizeof(top_iph->flow_lbl)); + top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family); + + if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP) + dsfield = 0; + else + dsfield = XFRM_MODE_SKB_CB(skb)->tos; + dsfield = INET_ECN_encapsulate(dsfield, XFRM_MODE_SKB_CB(skb)->tos); + if (x->props.flags & XFRM_STATE_NOECN) + dsfield &= ~INET_ECN_MASK; + ipv6_change_dsfield(top_iph, 0, dsfield); + top_iph->hop_limit = ip6_dst_hoplimit(xfrm_dst_child(dst)); + top_iph->saddr = *(struct in6_addr *)&x->props.saddr; + top_iph->daddr = *(struct in6_addr *)&x->id.daddr; + return 0; +} + +static int xfrm6_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb) +{ + struct ipv6hdr *top_iph; + struct ip_beet_phdr *ph; + int optlen, hdr_len; + + hdr_len = 0; + optlen = XFRM_MODE_SKB_CB(skb)->optlen; + if (unlikely(optlen)) + hdr_len += IPV4_BEET_PHMAXLEN - (optlen & 4); + + skb_set_network_header(skb, -x->props.header_len - hdr_len); + if (x->sel.family != AF_INET6) + skb->network_header += IPV4_BEET_PHMAXLEN; + skb->mac_header = skb->network_header + + offsetof(struct ipv6hdr, nexthdr); + skb->transport_header = skb->network_header + sizeof(*top_iph); + ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdr_len); + + xfrm6_beet_make_header(skb); + + top_iph = ipv6_hdr(skb); + if (unlikely(optlen)) { + if (WARN_ON(optlen < 0)) + return -EINVAL; + + ph->padlen = 4 - (optlen & 4); + ph->hdrlen = optlen / 8; + ph->nexthdr = top_iph->nexthdr; + if (ph->padlen) + memset(ph + 1, IPOPT_NOP, ph->padlen); + + top_iph->nexthdr = IPPROTO_BEETPH; + } + + top_iph->saddr = *(struct in6_addr *)&x->props.saddr; + top_iph->daddr = *(struct in6_addr *)&x->id.daddr; + return 0; +} +#endif + +/* Add encapsulation header. + * + * On exit, the transport header will be set to the start of the + * encapsulation header to be filled in by x->type->output and the mac + * header will be set to the nextheader (protocol for IPv4) field of the + * extension header directly preceding the encapsulation header, or in + * its absence, that of the top IP header. + * The value of the network header will always point to the top IP header + * while skb->data will point to the payload. + */ +static int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb) +{ + int err; + + err = xfrm_inner_extract_output(x, skb); + if (err) + return err; + + IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE; + skb->protocol = htons(ETH_P_IP); + + switch (x->outer_mode.encap) { + case XFRM_MODE_BEET: + return xfrm4_beet_encap_add(x, skb); + case XFRM_MODE_TUNNEL: + return xfrm4_tunnel_encap_add(x, skb); + } + + WARN_ON_ONCE(1); + return -EOPNOTSUPP; +} + +static int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb) +{ +#if IS_ENABLED(CONFIG_IPV6) + int err; + + err = xfrm_inner_extract_output(x, skb); + if (err) + return err; + + skb->ignore_df = 1; + skb->protocol = htons(ETH_P_IPV6); + + switch (x->outer_mode.encap) { + case XFRM_MODE_BEET: + return xfrm6_beet_encap_add(x, skb); + case XFRM_MODE_TUNNEL: + return xfrm6_tunnel_encap_add(x, skb); + default: + WARN_ON_ONCE(1); + return -EOPNOTSUPP; + } +#endif + WARN_ON_ONCE(1); + return -EAFNOSUPPORT; +} + +static int xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb) +{ + switch (x->outer_mode.encap) { + case XFRM_MODE_BEET: + case XFRM_MODE_TUNNEL: + if (x->outer_mode.family == AF_INET) + return xfrm4_prepare_output(x, skb); + if (x->outer_mode.family == AF_INET6) + return xfrm6_prepare_output(x, skb); + break; + case XFRM_MODE_TRANSPORT: + if (x->outer_mode.family == AF_INET) + return xfrm4_transport_output(x, skb); + if (x->outer_mode.family == AF_INET6) + return xfrm6_transport_output(x, skb); + break; + case XFRM_MODE_ROUTEOPTIMIZATION: + if (x->outer_mode.family == AF_INET6) + return xfrm6_ro_output(x, skb); + WARN_ON_ONCE(1); + break; + default: + WARN_ON_ONCE(1); + break; + } + + return -EOPNOTSUPP; +} + +#if IS_ENABLED(CONFIG_NET_PKTGEN) +int pktgen_xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb) +{ + return xfrm_outer_mode_output(x, skb); +} +EXPORT_SYMBOL_GPL(pktgen_xfrm_outer_mode_output); +#endif + +static int xfrm_output_one(struct sk_buff *skb, int err) +{ + struct dst_entry *dst = skb_dst(skb); + struct xfrm_state *x = dst->xfrm; + struct net *net = xs_net(x); + + if (err <= 0) + goto resume; + + do { + err = xfrm_skb_check_space(skb); + if (err) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); + goto error_nolock; + } + + skb->mark = xfrm_smark_get(skb->mark, x); + + err = xfrm_outer_mode_output(x, skb); + if (err) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR); + goto error_nolock; + } + + spin_lock_bh(&x->lock); + + if (unlikely(x->km.state != XFRM_STATE_VALID)) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID); + err = -EINVAL; + goto error; + } + + err = xfrm_state_check_expire(x); + if (err) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED); + goto error; + } + + err = xfrm_replay_overflow(x, skb); + if (err) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR); + goto error; + } + + x->curlft.bytes += skb->len; + x->curlft.packets++; + + spin_unlock_bh(&x->lock); + + skb_dst_force(skb); + if (!skb_dst(skb)) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); + err = -EHOSTUNREACH; + goto error_nolock; + } + + if (xfrm_offload(skb)) { + x->type_offload->encap(x, skb); + } else { + /* Inner headers are invalid now. */ + skb->encapsulation = 0; + + err = x->type->output(x, skb); + if (err == -EINPROGRESS) + goto out; + } + +resume: + if (err) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR); + goto error_nolock; + } + + dst = skb_dst_pop(skb); + if (!dst) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); + err = -EHOSTUNREACH; + goto error_nolock; + } + skb_dst_set(skb, dst); + x = dst->xfrm; + } while (x && !(x->outer_mode.flags & XFRM_MODE_FLAG_TUNNEL)); + + return 0; + +error: + spin_unlock_bh(&x->lock); +error_nolock: + kfree_skb(skb); +out: + return err; +} + +int xfrm_output_resume(struct sock *sk, struct sk_buff *skb, int err) +{ + struct net *net = xs_net(skb_dst(skb)->xfrm); + + while (likely((err = xfrm_output_one(skb, err)) == 0)) { + nf_reset_ct(skb); + + err = skb_dst(skb)->ops->local_out(net, sk, skb); + if (unlikely(err != 1)) + goto out; + + if (!skb_dst(skb)->xfrm) + return dst_output(net, sk, skb); + + err = nf_hook(skb_dst(skb)->ops->family, + NF_INET_POST_ROUTING, net, sk, skb, + NULL, skb_dst(skb)->dev, xfrm_output2); + if (unlikely(err != 1)) + goto out; + } + + if (err == -EINPROGRESS) + err = 0; + +out: + return err; +} +EXPORT_SYMBOL_GPL(xfrm_output_resume); + +static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb) +{ + return xfrm_output_resume(sk, skb, 1); +} + +static int xfrm_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb) +{ + struct sk_buff *segs, *nskb; + + BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_GSO_CB_OFFSET); + BUILD_BUG_ON(sizeof(*IP6CB(skb)) > SKB_GSO_CB_OFFSET); + segs = skb_gso_segment(skb, 0); + kfree_skb(skb); + if (IS_ERR(segs)) + return PTR_ERR(segs); + if (segs == NULL) + return -EINVAL; + + skb_list_walk_safe(segs, segs, nskb) { + int err; + + skb_mark_not_on_list(segs); + err = xfrm_output2(net, sk, segs); + + if (unlikely(err)) { + kfree_skb_list(nskb); + return err; + } + } + + return 0; +} + +/* For partial checksum offload, the outer header checksum is calculated + * by software and the inner header checksum is calculated by hardware. + * This requires hardware to know the inner packet type to calculate + * the inner header checksum. Save inner ip protocol here to avoid + * traversing the packet in the vendor's xmit code. + * For IPsec tunnel mode save the ip protocol from the IP header of the + * plain text packet. Otherwise If the encap type is IPIP, just save + * skb->inner_ipproto in any other case get the ip protocol from the IP + * header. + */ +static void xfrm_get_inner_ipproto(struct sk_buff *skb, struct xfrm_state *x) +{ + struct xfrm_offload *xo = xfrm_offload(skb); + const struct ethhdr *eth; + + if (!xo) + return; + + if (x->outer_mode.encap == XFRM_MODE_TUNNEL) { + switch (x->outer_mode.family) { + case AF_INET: + xo->inner_ipproto = ip_hdr(skb)->protocol; + break; + case AF_INET6: + xo->inner_ipproto = ipv6_hdr(skb)->nexthdr; + break; + default: + break; + } + + return; + } + + /* non-Tunnel Mode */ + if (!skb->encapsulation) + return; + + if (skb->inner_protocol_type == ENCAP_TYPE_IPPROTO) { + xo->inner_ipproto = skb->inner_ipproto; + return; + } + + if (skb->inner_protocol_type != ENCAP_TYPE_ETHER) + return; + + eth = (struct ethhdr *)skb_inner_mac_header(skb); + + switch (ntohs(eth->h_proto)) { + case ETH_P_IPV6: + xo->inner_ipproto = inner_ipv6_hdr(skb)->nexthdr; + break; + case ETH_P_IP: + xo->inner_ipproto = inner_ip_hdr(skb)->protocol; + break; + } +} + +int xfrm_output(struct sock *sk, struct sk_buff *skb) +{ + struct net *net = dev_net(skb_dst(skb)->dev); + struct xfrm_state *x = skb_dst(skb)->xfrm; + int err; + + switch (x->outer_mode.family) { + case AF_INET: + memset(IPCB(skb), 0, sizeof(*IPCB(skb))); + IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED; + break; + case AF_INET6: + memset(IP6CB(skb), 0, sizeof(*IP6CB(skb))); + + IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED; + break; + } + + secpath_reset(skb); + + if (xfrm_dev_offload_ok(skb, x)) { + struct sec_path *sp; + + sp = secpath_set(skb); + if (!sp) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); + kfree_skb(skb); + return -ENOMEM; + } + + sp->olen++; + sp->xvec[sp->len++] = x; + xfrm_state_hold(x); + + xfrm_get_inner_ipproto(skb, x); + skb->encapsulation = 1; + + if (skb_is_gso(skb)) { + if (skb->inner_protocol) + return xfrm_output_gso(net, sk, skb); + + skb_shinfo(skb)->gso_type |= SKB_GSO_ESP; + goto out; + } + + if (x->xso.dev && x->xso.dev->features & NETIF_F_HW_ESP_TX_CSUM) + goto out; + } else { + if (skb_is_gso(skb)) + return xfrm_output_gso(net, sk, skb); + } + + if (skb->ip_summed == CHECKSUM_PARTIAL) { + err = skb_checksum_help(skb); + if (err) { + XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR); + kfree_skb(skb); + return err; + } + } + +out: + return xfrm_output2(net, sk, skb); +} +EXPORT_SYMBOL_GPL(xfrm_output); + +static int xfrm4_tunnel_check_size(struct sk_buff *skb) +{ + int mtu, ret = 0; + + if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE) + goto out; + + if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df) + goto out; + + mtu = dst_mtu(skb_dst(skb)); + if ((!skb_is_gso(skb) && skb->len > mtu) || + (skb_is_gso(skb) && + !skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) { + skb->protocol = htons(ETH_P_IP); + + if (skb->sk) + xfrm_local_error(skb, mtu); + else + icmp_send(skb, ICMP_DEST_UNREACH, + ICMP_FRAG_NEEDED, htonl(mtu)); + ret = -EMSGSIZE; + } +out: + return ret; +} + +static int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb) +{ + int err; + + if (x->outer_mode.encap == XFRM_MODE_BEET && + ip_is_fragment(ip_hdr(skb))) { + net_warn_ratelimited("BEET mode doesn't support inner IPv4 fragments\n"); + return -EAFNOSUPPORT; + } + + err = xfrm4_tunnel_check_size(skb); + if (err) + return err; + + XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol; + + xfrm4_extract_header(skb); + return 0; +} + +#if IS_ENABLED(CONFIG_IPV6) +static int xfrm6_tunnel_check_size(struct sk_buff *skb) +{ + int mtu, ret = 0; + struct dst_entry *dst = skb_dst(skb); + + if (skb->ignore_df) + goto out; + + mtu = dst_mtu(dst); + if (mtu < IPV6_MIN_MTU) + mtu = IPV6_MIN_MTU; + + if ((!skb_is_gso(skb) && skb->len > mtu) || + (skb_is_gso(skb) && + !skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) { + skb->dev = dst->dev; + skb->protocol = htons(ETH_P_IPV6); + + if (xfrm6_local_dontfrag(skb->sk)) + ipv6_stub->xfrm6_local_rxpmtu(skb, mtu); + else if (skb->sk) + xfrm_local_error(skb, mtu); + else + icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); + ret = -EMSGSIZE; + } +out: + return ret; +} +#endif + +static int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb) +{ +#if IS_ENABLED(CONFIG_IPV6) + int err; + + err = xfrm6_tunnel_check_size(skb); + if (err) + return err; + + XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr; + + xfrm6_extract_header(skb); + return 0; +#else + WARN_ON_ONCE(1); + return -EAFNOSUPPORT; +#endif +} + +static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb) +{ + const struct xfrm_mode *inner_mode; + + if (x->sel.family == AF_UNSPEC) + inner_mode = xfrm_ip2inner_mode(x, + xfrm_af2proto(skb_dst(skb)->ops->family)); + else + inner_mode = &x->inner_mode; + + if (inner_mode == NULL) + return -EAFNOSUPPORT; + + switch (inner_mode->family) { + case AF_INET: + return xfrm4_extract_output(x, skb); + case AF_INET6: + return xfrm6_extract_output(x, skb); + } + + return -EAFNOSUPPORT; +} + +void xfrm_local_error(struct sk_buff *skb, int mtu) +{ + unsigned int proto; + struct xfrm_state_afinfo *afinfo; + + if (skb->protocol == htons(ETH_P_IP)) + proto = AF_INET; + else if (skb->protocol == htons(ETH_P_IPV6) && + skb->sk->sk_family == AF_INET6) + proto = AF_INET6; + else + return; + + afinfo = xfrm_state_get_afinfo(proto); + if (afinfo) { + afinfo->local_error(skb, mtu); + rcu_read_unlock(); + } +} +EXPORT_SYMBOL_GPL(xfrm_local_error); |