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- // SPDX-License-Identifier: GPL-2.0-or-later
- /*
- * Extension Header handling for IPv6
- * Linux INET6 implementation
- *
- * Authors:
- * Pedro Roque <roque@di.fc.ul.pt>
- * Andi Kleen <ak@muc.de>
- * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
- */
- /* Changes:
- * yoshfuji : ensure not to overrun while parsing
- * tlv options.
- * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
- * YOSHIFUJI Hideaki @USAGI Register inbound extension header
- * handlers as inet6_protocol{}.
- */
- #include <linux/errno.h>
- #include <linux/types.h>
- #include <linux/socket.h>
- #include <linux/sockios.h>
- #include <linux/net.h>
- #include <linux/netdevice.h>
- #include <linux/in6.h>
- #include <linux/icmpv6.h>
- #include <linux/slab.h>
- #include <linux/export.h>
- #include <net/dst.h>
- #include <net/sock.h>
- #include <net/snmp.h>
- #include <net/ipv6.h>
- #include <net/protocol.h>
- #include <net/transp_v6.h>
- #include <net/rawv6.h>
- #include <net/ndisc.h>
- #include <net/ip6_route.h>
- #include <net/addrconf.h>
- #include <net/calipso.h>
- #if IS_ENABLED(CONFIG_IPV6_MIP6)
- #include <net/xfrm.h>
- #endif
- #include <linux/seg6.h>
- #include <net/seg6.h>
- #ifdef CONFIG_IPV6_SEG6_HMAC
- #include <net/seg6_hmac.h>
- #endif
- #include <net/rpl.h>
- #include <linux/uaccess.h>
- /*
- * Parsing tlv encoded headers.
- *
- * Parsing function "func" returns true, if parsing succeed
- * and false, if it failed.
- * It MUST NOT touch skb->h.
- */
- struct tlvtype_proc {
- int type;
- bool (*func)(struct sk_buff *skb, int offset);
- };
- /*********************
- Generic functions
- *********************/
- /* An unknown option is detected, decide what to do */
- static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff,
- bool disallow_unknowns)
- {
- if (disallow_unknowns) {
- /* If unknown TLVs are disallowed by configuration
- * then always silently drop packet. Note this also
- * means no ICMP parameter problem is sent which
- * could be a good property to mitigate a reflection DOS
- * attack.
- */
- goto drop;
- }
- switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
- case 0: /* ignore */
- return true;
- case 1: /* drop packet */
- break;
- case 3: /* Send ICMP if not a multicast address and drop packet */
- /* Actually, it is redundant check. icmp_send
- will recheck in any case.
- */
- if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
- break;
- fallthrough;
- case 2: /* send ICMP PARM PROB regardless and drop packet */
- icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
- return false;
- }
- drop:
- kfree_skb(skb);
- return false;
- }
- /* Parse tlv encoded option header (hop-by-hop or destination) */
- static bool ip6_parse_tlv(const struct tlvtype_proc *procs,
- struct sk_buff *skb,
- int max_count)
- {
- int len = (skb_transport_header(skb)[1] + 1) << 3;
- const unsigned char *nh = skb_network_header(skb);
- int off = skb_network_header_len(skb);
- const struct tlvtype_proc *curr;
- bool disallow_unknowns = false;
- int tlv_count = 0;
- int padlen = 0;
- if (unlikely(max_count < 0)) {
- disallow_unknowns = true;
- max_count = -max_count;
- }
- if (skb_transport_offset(skb) + len > skb_headlen(skb))
- goto bad;
- off += 2;
- len -= 2;
- while (len > 0) {
- int optlen, i;
- if (nh[off] == IPV6_TLV_PAD1) {
- padlen++;
- if (padlen > 7)
- goto bad;
- off++;
- len--;
- continue;
- }
- if (len < 2)
- goto bad;
- optlen = nh[off + 1] + 2;
- if (optlen > len)
- goto bad;
- if (nh[off] == IPV6_TLV_PADN) {
- /* RFC 2460 states that the purpose of PadN is
- * to align the containing header to multiples
- * of 8. 7 is therefore the highest valid value.
- * See also RFC 4942, Section 2.1.9.5.
- */
- padlen += optlen;
- if (padlen > 7)
- goto bad;
- /* RFC 4942 recommends receiving hosts to
- * actively check PadN payload to contain
- * only zeroes.
- */
- for (i = 2; i < optlen; i++) {
- if (nh[off + i] != 0)
- goto bad;
- }
- } else {
- tlv_count++;
- if (tlv_count > max_count)
- goto bad;
- for (curr = procs; curr->type >= 0; curr++) {
- if (curr->type == nh[off]) {
- /* type specific length/alignment
- checks will be performed in the
- func(). */
- if (curr->func(skb, off) == false)
- return false;
- break;
- }
- }
- if (curr->type < 0 &&
- !ip6_tlvopt_unknown(skb, off, disallow_unknowns))
- return false;
- padlen = 0;
- }
- off += optlen;
- len -= optlen;
- }
- if (len == 0)
- return true;
- bad:
- kfree_skb(skb);
- return false;
- }
- /*****************************
- Destination options header.
- *****************************/
- #if IS_ENABLED(CONFIG_IPV6_MIP6)
- static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
- {
- struct ipv6_destopt_hao *hao;
- struct inet6_skb_parm *opt = IP6CB(skb);
- struct ipv6hdr *ipv6h = ipv6_hdr(skb);
- int ret;
- if (opt->dsthao) {
- net_dbg_ratelimited("hao duplicated\n");
- goto discard;
- }
- opt->dsthao = opt->dst1;
- opt->dst1 = 0;
- hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
- if (hao->length != 16) {
- net_dbg_ratelimited("hao invalid option length = %d\n",
- hao->length);
- goto discard;
- }
- if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
- net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
- &hao->addr);
- goto discard;
- }
- ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
- (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
- if (unlikely(ret < 0))
- goto discard;
- if (skb_cloned(skb)) {
- if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
- goto discard;
- /* update all variable using below by copied skbuff */
- hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
- optoff);
- ipv6h = ipv6_hdr(skb);
- }
- if (skb->ip_summed == CHECKSUM_COMPLETE)
- skb->ip_summed = CHECKSUM_NONE;
- swap(ipv6h->saddr, hao->addr);
- if (skb->tstamp == 0)
- __net_timestamp(skb);
- return true;
- discard:
- kfree_skb(skb);
- return false;
- }
- #endif
- static const struct tlvtype_proc tlvprocdestopt_lst[] = {
- #if IS_ENABLED(CONFIG_IPV6_MIP6)
- {
- .type = IPV6_TLV_HAO,
- .func = ipv6_dest_hao,
- },
- #endif
- {-1, NULL}
- };
- static int ipv6_destopt_rcv(struct sk_buff *skb)
- {
- struct inet6_dev *idev = __in6_dev_get(skb->dev);
- struct inet6_skb_parm *opt = IP6CB(skb);
- #if IS_ENABLED(CONFIG_IPV6_MIP6)
- __u16 dstbuf;
- #endif
- struct dst_entry *dst = skb_dst(skb);
- struct net *net = dev_net(skb->dev);
- int extlen;
- if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
- !pskb_may_pull(skb, (skb_transport_offset(skb) +
- ((skb_transport_header(skb)[1] + 1) << 3)))) {
- __IP6_INC_STATS(dev_net(dst->dev), idev,
- IPSTATS_MIB_INHDRERRORS);
- fail_and_free:
- kfree_skb(skb);
- return -1;
- }
- extlen = (skb_transport_header(skb)[1] + 1) << 3;
- if (extlen > net->ipv6.sysctl.max_dst_opts_len)
- goto fail_and_free;
- opt->lastopt = opt->dst1 = skb_network_header_len(skb);
- #if IS_ENABLED(CONFIG_IPV6_MIP6)
- dstbuf = opt->dst1;
- #endif
- if (ip6_parse_tlv(tlvprocdestopt_lst, skb,
- net->ipv6.sysctl.max_dst_opts_cnt)) {
- skb->transport_header += extlen;
- opt = IP6CB(skb);
- #if IS_ENABLED(CONFIG_IPV6_MIP6)
- opt->nhoff = dstbuf;
- #else
- opt->nhoff = opt->dst1;
- #endif
- return 1;
- }
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
- return -1;
- }
- static void seg6_update_csum(struct sk_buff *skb)
- {
- struct ipv6_sr_hdr *hdr;
- struct in6_addr *addr;
- __be32 from, to;
- /* srh is at transport offset and seg_left is already decremented
- * but daddr is not yet updated with next segment
- */
- hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
- addr = hdr->segments + hdr->segments_left;
- hdr->segments_left++;
- from = *(__be32 *)hdr;
- hdr->segments_left--;
- to = *(__be32 *)hdr;
- /* update skb csum with diff resulting from seg_left decrement */
- update_csum_diff4(skb, from, to);
- /* compute csum diff between current and next segment and update */
- update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr),
- (__be32 *)addr);
- }
- static int ipv6_srh_rcv(struct sk_buff *skb)
- {
- struct inet6_skb_parm *opt = IP6CB(skb);
- struct net *net = dev_net(skb->dev);
- struct ipv6_sr_hdr *hdr;
- struct inet6_dev *idev;
- struct in6_addr *addr;
- int accept_seg6;
- hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
- idev = __in6_dev_get(skb->dev);
- accept_seg6 = net->ipv6.devconf_all->seg6_enabled;
- if (accept_seg6 > idev->cnf.seg6_enabled)
- accept_seg6 = idev->cnf.seg6_enabled;
- if (!accept_seg6) {
- kfree_skb(skb);
- return -1;
- }
- #ifdef CONFIG_IPV6_SEG6_HMAC
- if (!seg6_hmac_validate_skb(skb)) {
- kfree_skb(skb);
- return -1;
- }
- #endif
- looped_back:
- if (hdr->segments_left == 0) {
- if (hdr->nexthdr == NEXTHDR_IPV6) {
- int offset = (hdr->hdrlen + 1) << 3;
- skb_postpull_rcsum(skb, skb_network_header(skb),
- skb_network_header_len(skb));
- if (!pskb_pull(skb, offset)) {
- kfree_skb(skb);
- return -1;
- }
- skb_postpull_rcsum(skb, skb_transport_header(skb),
- offset);
- skb_reset_network_header(skb);
- skb_reset_transport_header(skb);
- skb->encapsulation = 0;
- __skb_tunnel_rx(skb, skb->dev, net);
- netif_rx(skb);
- return -1;
- }
- opt->srcrt = skb_network_header_len(skb);
- opt->lastopt = opt->srcrt;
- skb->transport_header += (hdr->hdrlen + 1) << 3;
- opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
- return 1;
- }
- if (hdr->segments_left >= (hdr->hdrlen >> 1)) {
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
- icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
- ((&hdr->segments_left) -
- skb_network_header(skb)));
- return -1;
- }
- if (skb_cloned(skb)) {
- if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
- __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_OUTDISCARDS);
- kfree_skb(skb);
- return -1;
- }
- }
- hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
- hdr->segments_left--;
- addr = hdr->segments + hdr->segments_left;
- skb_push(skb, sizeof(struct ipv6hdr));
- if (skb->ip_summed == CHECKSUM_COMPLETE)
- seg6_update_csum(skb);
- ipv6_hdr(skb)->daddr = *addr;
- skb_dst_drop(skb);
- ip6_route_input(skb);
- if (skb_dst(skb)->error) {
- dst_input(skb);
- return -1;
- }
- if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
- if (ipv6_hdr(skb)->hop_limit <= 1) {
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
- icmpv6_send(skb, ICMPV6_TIME_EXCEED,
- ICMPV6_EXC_HOPLIMIT, 0);
- kfree_skb(skb);
- return -1;
- }
- ipv6_hdr(skb)->hop_limit--;
- skb_pull(skb, sizeof(struct ipv6hdr));
- goto looped_back;
- }
- dst_input(skb);
- return -1;
- }
- static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
- {
- struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr;
- struct inet6_skb_parm *opt = IP6CB(skb);
- struct net *net = dev_net(skb->dev);
- struct inet6_dev *idev;
- struct ipv6hdr *oldhdr;
- struct in6_addr addr;
- unsigned char *buf;
- int accept_rpl_seg;
- int i, err;
- u64 n = 0;
- u32 r;
- idev = __in6_dev_get(skb->dev);
- accept_rpl_seg = net->ipv6.devconf_all->rpl_seg_enabled;
- if (accept_rpl_seg > idev->cnf.rpl_seg_enabled)
- accept_rpl_seg = idev->cnf.rpl_seg_enabled;
- if (!accept_rpl_seg) {
- kfree_skb(skb);
- return -1;
- }
- looped_back:
- hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
- if (hdr->segments_left == 0) {
- if (hdr->nexthdr == NEXTHDR_IPV6) {
- int offset = (hdr->hdrlen + 1) << 3;
- skb_postpull_rcsum(skb, skb_network_header(skb),
- skb_network_header_len(skb));
- if (!pskb_pull(skb, offset)) {
- kfree_skb(skb);
- return -1;
- }
- skb_postpull_rcsum(skb, skb_transport_header(skb),
- offset);
- skb_reset_network_header(skb);
- skb_reset_transport_header(skb);
- skb->encapsulation = 0;
- __skb_tunnel_rx(skb, skb->dev, net);
- netif_rx(skb);
- return -1;
- }
- opt->srcrt = skb_network_header_len(skb);
- opt->lastopt = opt->srcrt;
- skb->transport_header += (hdr->hdrlen + 1) << 3;
- opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
- return 1;
- }
- if (!pskb_may_pull(skb, sizeof(*hdr))) {
- kfree_skb(skb);
- return -1;
- }
- n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre);
- r = do_div(n, (16 - hdr->cmpri));
- /* checks if calculation was without remainder and n fits into
- * unsigned char which is segments_left field. Should not be
- * higher than that.
- */
- if (r || (n + 1) > 255) {
- kfree_skb(skb);
- return -1;
- }
- if (hdr->segments_left > n + 1) {
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
- icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
- ((&hdr->segments_left) -
- skb_network_header(skb)));
- return -1;
- }
- if (skb_cloned(skb)) {
- if (pskb_expand_head(skb, IPV6_RPL_SRH_WORST_SWAP_SIZE, 0,
- GFP_ATOMIC)) {
- __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_OUTDISCARDS);
- kfree_skb(skb);
- return -1;
- }
- } else {
- err = skb_cow_head(skb, IPV6_RPL_SRH_WORST_SWAP_SIZE);
- if (unlikely(err)) {
- kfree_skb(skb);
- return -1;
- }
- }
- hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
- if (!pskb_may_pull(skb, ipv6_rpl_srh_size(n, hdr->cmpri,
- hdr->cmpre))) {
- kfree_skb(skb);
- return -1;
- }
- hdr->segments_left--;
- i = n - hdr->segments_left;
- buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC);
- if (unlikely(!buf)) {
- kfree_skb(skb);
- return -1;
- }
- ohdr = (struct ipv6_rpl_sr_hdr *)buf;
- ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
- chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
- if ((ipv6_addr_type(&ipv6_hdr(skb)->daddr) & IPV6_ADDR_MULTICAST) ||
- (ipv6_addr_type(&ohdr->rpl_segaddr[i]) & IPV6_ADDR_MULTICAST)) {
- kfree_skb(skb);
- kfree(buf);
- return -1;
- }
- err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1);
- if (err) {
- icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0);
- kfree_skb(skb);
- kfree(buf);
- return -1;
- }
- addr = ipv6_hdr(skb)->daddr;
- ipv6_hdr(skb)->daddr = ohdr->rpl_segaddr[i];
- ohdr->rpl_segaddr[i] = addr;
- ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n);
- oldhdr = ipv6_hdr(skb);
- skb_pull(skb, ((hdr->hdrlen + 1) << 3));
- skb_postpull_rcsum(skb, oldhdr,
- sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3));
- skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr));
- skb_reset_network_header(skb);
- skb_mac_header_rebuild(skb);
- skb_set_transport_header(skb, sizeof(struct ipv6hdr));
- memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr));
- memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3);
- ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
- skb_postpush_rcsum(skb, ipv6_hdr(skb),
- sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3));
- kfree(buf);
- skb_dst_drop(skb);
- ip6_route_input(skb);
- if (skb_dst(skb)->error) {
- dst_input(skb);
- return -1;
- }
- if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
- if (ipv6_hdr(skb)->hop_limit <= 1) {
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
- icmpv6_send(skb, ICMPV6_TIME_EXCEED,
- ICMPV6_EXC_HOPLIMIT, 0);
- kfree_skb(skb);
- return -1;
- }
- ipv6_hdr(skb)->hop_limit--;
- skb_pull(skb, sizeof(struct ipv6hdr));
- goto looped_back;
- }
- dst_input(skb);
- return -1;
- }
- /********************************
- Routing header.
- ********************************/
- /* called with rcu_read_lock() */
- static int ipv6_rthdr_rcv(struct sk_buff *skb)
- {
- struct inet6_dev *idev = __in6_dev_get(skb->dev);
- struct inet6_skb_parm *opt = IP6CB(skb);
- struct in6_addr *addr = NULL;
- struct in6_addr daddr;
- int n, i;
- struct ipv6_rt_hdr *hdr;
- struct rt0_hdr *rthdr;
- struct net *net = dev_net(skb->dev);
- int accept_source_route = net->ipv6.devconf_all->accept_source_route;
- idev = __in6_dev_get(skb->dev);
- if (idev && accept_source_route > idev->cnf.accept_source_route)
- accept_source_route = idev->cnf.accept_source_route;
- if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
- !pskb_may_pull(skb, (skb_transport_offset(skb) +
- ((skb_transport_header(skb)[1] + 1) << 3)))) {
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
- kfree_skb(skb);
- return -1;
- }
- hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
- if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
- skb->pkt_type != PACKET_HOST) {
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
- kfree_skb(skb);
- return -1;
- }
- switch (hdr->type) {
- case IPV6_SRCRT_TYPE_4:
- /* segment routing */
- return ipv6_srh_rcv(skb);
- case IPV6_SRCRT_TYPE_3:
- /* rpl segment routing */
- return ipv6_rpl_srh_rcv(skb);
- default:
- break;
- }
- looped_back:
- if (hdr->segments_left == 0) {
- switch (hdr->type) {
- #if IS_ENABLED(CONFIG_IPV6_MIP6)
- case IPV6_SRCRT_TYPE_2:
- /* Silently discard type 2 header unless it was
- * processed by own
- */
- if (!addr) {
- __IP6_INC_STATS(net, idev,
- IPSTATS_MIB_INADDRERRORS);
- kfree_skb(skb);
- return -1;
- }
- break;
- #endif
- default:
- break;
- }
- opt->lastopt = opt->srcrt = skb_network_header_len(skb);
- skb->transport_header += (hdr->hdrlen + 1) << 3;
- opt->dst0 = opt->dst1;
- opt->dst1 = 0;
- opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
- return 1;
- }
- switch (hdr->type) {
- #if IS_ENABLED(CONFIG_IPV6_MIP6)
- case IPV6_SRCRT_TYPE_2:
- if (accept_source_route < 0)
- goto unknown_rh;
- /* Silently discard invalid RTH type 2 */
- if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
- kfree_skb(skb);
- return -1;
- }
- break;
- #endif
- default:
- goto unknown_rh;
- }
- /*
- * This is the routing header forwarding algorithm from
- * RFC 2460, page 16.
- */
- n = hdr->hdrlen >> 1;
- if (hdr->segments_left > n) {
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
- icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
- ((&hdr->segments_left) -
- skb_network_header(skb)));
- return -1;
- }
- /* We are about to mangle packet header. Be careful!
- Do not damage packets queued somewhere.
- */
- if (skb_cloned(skb)) {
- /* the copy is a forwarded packet */
- if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
- __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
- IPSTATS_MIB_OUTDISCARDS);
- kfree_skb(skb);
- return -1;
- }
- hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
- }
- if (skb->ip_summed == CHECKSUM_COMPLETE)
- skb->ip_summed = CHECKSUM_NONE;
- i = n - --hdr->segments_left;
- rthdr = (struct rt0_hdr *) hdr;
- addr = rthdr->addr;
- addr += i - 1;
- switch (hdr->type) {
- #if IS_ENABLED(CONFIG_IPV6_MIP6)
- case IPV6_SRCRT_TYPE_2:
- if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
- (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
- IPPROTO_ROUTING) < 0) {
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
- kfree_skb(skb);
- return -1;
- }
- if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
- kfree_skb(skb);
- return -1;
- }
- break;
- #endif
- default:
- break;
- }
- if (ipv6_addr_is_multicast(addr)) {
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
- kfree_skb(skb);
- return -1;
- }
- daddr = *addr;
- *addr = ipv6_hdr(skb)->daddr;
- ipv6_hdr(skb)->daddr = daddr;
- skb_dst_drop(skb);
- ip6_route_input(skb);
- if (skb_dst(skb)->error) {
- skb_push(skb, skb->data - skb_network_header(skb));
- dst_input(skb);
- return -1;
- }
- if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
- if (ipv6_hdr(skb)->hop_limit <= 1) {
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
- icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
- 0);
- kfree_skb(skb);
- return -1;
- }
- ipv6_hdr(skb)->hop_limit--;
- goto looped_back;
- }
- skb_push(skb, skb->data - skb_network_header(skb));
- dst_input(skb);
- return -1;
- unknown_rh:
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
- icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
- (&hdr->type) - skb_network_header(skb));
- return -1;
- }
- static const struct inet6_protocol rthdr_protocol = {
- .handler = ipv6_rthdr_rcv,
- .flags = INET6_PROTO_NOPOLICY,
- };
- static const struct inet6_protocol destopt_protocol = {
- .handler = ipv6_destopt_rcv,
- .flags = INET6_PROTO_NOPOLICY,
- };
- static const struct inet6_protocol nodata_protocol = {
- .handler = dst_discard,
- .flags = INET6_PROTO_NOPOLICY,
- };
- int __init ipv6_exthdrs_init(void)
- {
- int ret;
- ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
- if (ret)
- goto out;
- ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
- if (ret)
- goto out_rthdr;
- ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
- if (ret)
- goto out_destopt;
- out:
- return ret;
- out_destopt:
- inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
- out_rthdr:
- inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
- goto out;
- };
- void ipv6_exthdrs_exit(void)
- {
- inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
- inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
- inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
- }
- /**********************************
- Hop-by-hop options.
- **********************************/
- /*
- * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
- */
- static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
- {
- return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
- }
- static inline struct net *ipv6_skb_net(struct sk_buff *skb)
- {
- return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
- }
- /* Router Alert as of RFC 2711 */
- static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
- {
- const unsigned char *nh = skb_network_header(skb);
- if (nh[optoff + 1] == 2) {
- IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
- memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
- return true;
- }
- net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
- nh[optoff + 1]);
- kfree_skb(skb);
- return false;
- }
- /* Jumbo payload */
- static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
- {
- const unsigned char *nh = skb_network_header(skb);
- struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
- struct net *net = ipv6_skb_net(skb);
- u32 pkt_len;
- if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
- net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
- nh[optoff+1]);
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
- goto drop;
- }
- pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
- if (pkt_len <= IPV6_MAXPLEN) {
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
- icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
- return false;
- }
- if (ipv6_hdr(skb)->payload_len) {
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
- icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
- return false;
- }
- if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
- __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTRUNCATEDPKTS);
- goto drop;
- }
- if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
- goto drop;
- IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
- return true;
- drop:
- kfree_skb(skb);
- return false;
- }
- /* CALIPSO RFC 5570 */
- static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
- {
- const unsigned char *nh = skb_network_header(skb);
- if (nh[optoff + 1] < 8)
- goto drop;
- if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
- goto drop;
- if (!calipso_validate(skb, nh + optoff))
- goto drop;
- return true;
- drop:
- kfree_skb(skb);
- return false;
- }
- static const struct tlvtype_proc tlvprochopopt_lst[] = {
- {
- .type = IPV6_TLV_ROUTERALERT,
- .func = ipv6_hop_ra,
- },
- {
- .type = IPV6_TLV_JUMBO,
- .func = ipv6_hop_jumbo,
- },
- {
- .type = IPV6_TLV_CALIPSO,
- .func = ipv6_hop_calipso,
- },
- { -1, }
- };
- int ipv6_parse_hopopts(struct sk_buff *skb)
- {
- struct inet6_skb_parm *opt = IP6CB(skb);
- struct net *net = dev_net(skb->dev);
- int extlen;
- /*
- * skb_network_header(skb) is equal to skb->data, and
- * skb_network_header_len(skb) is always equal to
- * sizeof(struct ipv6hdr) by definition of
- * hop-by-hop options.
- */
- if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
- !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
- ((skb_transport_header(skb)[1] + 1) << 3)))) {
- fail_and_free:
- kfree_skb(skb);
- return -1;
- }
- extlen = (skb_transport_header(skb)[1] + 1) << 3;
- if (extlen > net->ipv6.sysctl.max_hbh_opts_len)
- goto fail_and_free;
- opt->flags |= IP6SKB_HOPBYHOP;
- if (ip6_parse_tlv(tlvprochopopt_lst, skb,
- net->ipv6.sysctl.max_hbh_opts_cnt)) {
- skb->transport_header += extlen;
- opt = IP6CB(skb);
- opt->nhoff = sizeof(struct ipv6hdr);
- return 1;
- }
- return -1;
- }
- /*
- * Creating outbound headers.
- *
- * "build" functions work when skb is filled from head to tail (datagram)
- * "push" functions work when headers are added from tail to head (tcp)
- *
- * In both cases we assume, that caller reserved enough room
- * for headers.
- */
- static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
- struct ipv6_rt_hdr *opt,
- struct in6_addr **addr_p, struct in6_addr *saddr)
- {
- struct rt0_hdr *phdr, *ihdr;
- int hops;
- ihdr = (struct rt0_hdr *) opt;
- phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
- memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
- hops = ihdr->rt_hdr.hdrlen >> 1;
- if (hops > 1)
- memcpy(phdr->addr, ihdr->addr + 1,
- (hops - 1) * sizeof(struct in6_addr));
- phdr->addr[hops - 1] = **addr_p;
- *addr_p = ihdr->addr;
- phdr->rt_hdr.nexthdr = *proto;
- *proto = NEXTHDR_ROUTING;
- }
- static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,
- struct ipv6_rt_hdr *opt,
- struct in6_addr **addr_p, struct in6_addr *saddr)
- {
- struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
- int plen, hops;
- sr_ihdr = (struct ipv6_sr_hdr *)opt;
- plen = (sr_ihdr->hdrlen + 1) << 3;
- sr_phdr = skb_push(skb, plen);
- memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
- hops = sr_ihdr->first_segment + 1;
- memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
- (hops - 1) * sizeof(struct in6_addr));
- sr_phdr->segments[0] = **addr_p;
- *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
- if (sr_ihdr->hdrlen > hops * 2) {
- int tlvs_offset, tlvs_length;
- tlvs_offset = (1 + hops * 2) << 3;
- tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
- memcpy((char *)sr_phdr + tlvs_offset,
- (char *)sr_ihdr + tlvs_offset, tlvs_length);
- }
- #ifdef CONFIG_IPV6_SEG6_HMAC
- if (sr_has_hmac(sr_phdr)) {
- struct net *net = NULL;
- if (skb->dev)
- net = dev_net(skb->dev);
- else if (skb->sk)
- net = sock_net(skb->sk);
- WARN_ON(!net);
- if (net)
- seg6_push_hmac(net, saddr, sr_phdr);
- }
- #endif
- sr_phdr->nexthdr = *proto;
- *proto = NEXTHDR_ROUTING;
- }
- static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
- struct ipv6_rt_hdr *opt,
- struct in6_addr **addr_p, struct in6_addr *saddr)
- {
- switch (opt->type) {
- case IPV6_SRCRT_TYPE_0:
- case IPV6_SRCRT_STRICT:
- case IPV6_SRCRT_TYPE_2:
- ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
- break;
- case IPV6_SRCRT_TYPE_4:
- ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
- break;
- default:
- break;
- }
- }
- static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
- {
- struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
- memcpy(h, opt, ipv6_optlen(opt));
- h->nexthdr = *proto;
- *proto = type;
- }
- void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
- u8 *proto,
- struct in6_addr **daddr, struct in6_addr *saddr)
- {
- if (opt->srcrt) {
- ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
- /*
- * IPV6_RTHDRDSTOPTS is ignored
- * unless IPV6_RTHDR is set (RFC3542).
- */
- if (opt->dst0opt)
- ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
- }
- if (opt->hopopt)
- ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
- }
- void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
- {
- if (opt->dst1opt)
- ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
- }
- EXPORT_SYMBOL(ipv6_push_frag_opts);
- struct ipv6_txoptions *
- ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
- {
- struct ipv6_txoptions *opt2;
- opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
- if (opt2) {
- long dif = (char *)opt2 - (char *)opt;
- memcpy(opt2, opt, opt->tot_len);
- if (opt2->hopopt)
- *((char **)&opt2->hopopt) += dif;
- if (opt2->dst0opt)
- *((char **)&opt2->dst0opt) += dif;
- if (opt2->dst1opt)
- *((char **)&opt2->dst1opt) += dif;
- if (opt2->srcrt)
- *((char **)&opt2->srcrt) += dif;
- refcount_set(&opt2->refcnt, 1);
- }
- return opt2;
- }
- EXPORT_SYMBOL_GPL(ipv6_dup_options);
- static void ipv6_renew_option(int renewtype,
- struct ipv6_opt_hdr **dest,
- struct ipv6_opt_hdr *old,
- struct ipv6_opt_hdr *new,
- int newtype, char **p)
- {
- struct ipv6_opt_hdr *src;
- src = (renewtype == newtype ? new : old);
- if (!src)
- return;
- memcpy(*p, src, ipv6_optlen(src));
- *dest = (struct ipv6_opt_hdr *)*p;
- *p += CMSG_ALIGN(ipv6_optlen(*dest));
- }
- /**
- * ipv6_renew_options - replace a specific ext hdr with a new one.
- *
- * @sk: sock from which to allocate memory
- * @opt: original options
- * @newtype: option type to replace in @opt
- * @newopt: new option of type @newtype to replace (user-mem)
- *
- * Returns a new set of options which is a copy of @opt with the
- * option type @newtype replaced with @newopt.
- *
- * @opt may be NULL, in which case a new set of options is returned
- * containing just @newopt.
- *
- * @newopt may be NULL, in which case the specified option type is
- * not copied into the new set of options.
- *
- * The new set of options is allocated from the socket option memory
- * buffer of @sk.
- */
- struct ipv6_txoptions *
- ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
- int newtype, struct ipv6_opt_hdr *newopt)
- {
- int tot_len = 0;
- char *p;
- struct ipv6_txoptions *opt2;
- if (opt) {
- if (newtype != IPV6_HOPOPTS && opt->hopopt)
- tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
- if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
- tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
- if (newtype != IPV6_RTHDR && opt->srcrt)
- tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
- if (newtype != IPV6_DSTOPTS && opt->dst1opt)
- tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
- }
- if (newopt)
- tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
- if (!tot_len)
- return NULL;
- tot_len += sizeof(*opt2);
- opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
- if (!opt2)
- return ERR_PTR(-ENOBUFS);
- memset(opt2, 0, tot_len);
- refcount_set(&opt2->refcnt, 1);
- opt2->tot_len = tot_len;
- p = (char *)(opt2 + 1);
- ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
- (opt ? opt->hopopt : NULL),
- newopt, newtype, &p);
- ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
- (opt ? opt->dst0opt : NULL),
- newopt, newtype, &p);
- ipv6_renew_option(IPV6_RTHDR,
- (struct ipv6_opt_hdr **)&opt2->srcrt,
- (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
- newopt, newtype, &p);
- ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
- (opt ? opt->dst1opt : NULL),
- newopt, newtype, &p);
- opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
- (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
- (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
- opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
- return opt2;
- }
- struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
- struct ipv6_txoptions *opt)
- {
- /*
- * ignore the dest before srcrt unless srcrt is being included.
- * --yoshfuji
- */
- if (opt && opt->dst0opt && !opt->srcrt) {
- if (opt_space != opt) {
- memcpy(opt_space, opt, sizeof(*opt_space));
- opt = opt_space;
- }
- opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
- opt->dst0opt = NULL;
- }
- return opt;
- }
- EXPORT_SYMBOL_GPL(ipv6_fixup_options);
- /**
- * fl6_update_dst - update flowi destination address with info given
- * by srcrt option, if any.
- *
- * @fl6: flowi6 for which daddr is to be updated
- * @opt: struct ipv6_txoptions in which to look for srcrt opt
- * @orig: copy of original daddr address if modified
- *
- * Returns NULL if no txoptions or no srcrt, otherwise returns orig
- * and initial value of fl6->daddr set in orig
- */
- struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
- const struct ipv6_txoptions *opt,
- struct in6_addr *orig)
- {
- if (!opt || !opt->srcrt)
- return NULL;
- *orig = fl6->daddr;
- switch (opt->srcrt->type) {
- case IPV6_SRCRT_TYPE_0:
- case IPV6_SRCRT_STRICT:
- case IPV6_SRCRT_TYPE_2:
- fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
- break;
- case IPV6_SRCRT_TYPE_4:
- {
- struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
- fl6->daddr = srh->segments[srh->segments_left];
- break;
- }
- default:
- return NULL;
- }
- return orig;
- }
- EXPORT_SYMBOL_GPL(fl6_update_dst);
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