diff options
Diffstat (limited to 'net/ipv6/rpl_iptunnel.c')
-rw-r--r-- | net/ipv6/rpl_iptunnel.c | 381 |
1 files changed, 381 insertions, 0 deletions
diff --git a/net/ipv6/rpl_iptunnel.c b/net/ipv6/rpl_iptunnel.c new file mode 100644 index 000000000..5fdf3ebb9 --- /dev/null +++ b/net/ipv6/rpl_iptunnel.c @@ -0,0 +1,381 @@ +// SPDX-License-Identifier: GPL-2.0-only +/** + * Authors: + * (C) 2020 Alexander Aring <alex.aring@gmail.com> + */ + +#include <linux/rpl_iptunnel.h> + +#include <net/dst_cache.h> +#include <net/ip6_route.h> +#include <net/lwtunnel.h> +#include <net/ipv6.h> +#include <net/rpl.h> + +struct rpl_iptunnel_encap { + struct ipv6_rpl_sr_hdr srh[0]; +}; + +struct rpl_lwt { + struct dst_cache cache; + struct rpl_iptunnel_encap tuninfo; +}; + +static inline struct rpl_lwt *rpl_lwt_lwtunnel(struct lwtunnel_state *lwt) +{ + return (struct rpl_lwt *)lwt->data; +} + +static inline struct rpl_iptunnel_encap * +rpl_encap_lwtunnel(struct lwtunnel_state *lwt) +{ + return &rpl_lwt_lwtunnel(lwt)->tuninfo; +} + +static const struct nla_policy rpl_iptunnel_policy[RPL_IPTUNNEL_MAX + 1] = { + [RPL_IPTUNNEL_SRH] = { .type = NLA_BINARY }, +}; + +static bool rpl_validate_srh(struct net *net, struct ipv6_rpl_sr_hdr *srh, + size_t seglen) +{ + int err; + + if ((srh->hdrlen << 3) != seglen) + return false; + + /* check at least one segment and seglen fit with segments_left */ + if (!srh->segments_left || + (srh->segments_left * sizeof(struct in6_addr)) != seglen) + return false; + + if (srh->cmpri || srh->cmpre) + return false; + + err = ipv6_chk_rpl_srh_loop(net, srh->rpl_segaddr, + srh->segments_left); + if (err) + return false; + + if (ipv6_addr_type(&srh->rpl_segaddr[srh->segments_left - 1]) & + IPV6_ADDR_MULTICAST) + return false; + + return true; +} + +static int rpl_build_state(struct net *net, struct nlattr *nla, + unsigned int family, const void *cfg, + struct lwtunnel_state **ts, + struct netlink_ext_ack *extack) +{ + struct nlattr *tb[RPL_IPTUNNEL_MAX + 1]; + struct lwtunnel_state *newts; + struct ipv6_rpl_sr_hdr *srh; + struct rpl_lwt *rlwt; + int err, srh_len; + + if (family != AF_INET6) + return -EINVAL; + + err = nla_parse_nested(tb, RPL_IPTUNNEL_MAX, nla, + rpl_iptunnel_policy, extack); + if (err < 0) + return err; + + if (!tb[RPL_IPTUNNEL_SRH]) + return -EINVAL; + + srh = nla_data(tb[RPL_IPTUNNEL_SRH]); + srh_len = nla_len(tb[RPL_IPTUNNEL_SRH]); + + if (srh_len < sizeof(*srh)) + return -EINVAL; + + /* verify that SRH is consistent */ + if (!rpl_validate_srh(net, srh, srh_len - sizeof(*srh))) + return -EINVAL; + + newts = lwtunnel_state_alloc(srh_len + sizeof(*rlwt)); + if (!newts) + return -ENOMEM; + + rlwt = rpl_lwt_lwtunnel(newts); + + err = dst_cache_init(&rlwt->cache, GFP_ATOMIC); + if (err) { + kfree(newts); + return err; + } + + memcpy(&rlwt->tuninfo.srh, srh, srh_len); + + newts->type = LWTUNNEL_ENCAP_RPL; + newts->flags |= LWTUNNEL_STATE_INPUT_REDIRECT; + newts->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT; + + *ts = newts; + + return 0; +} + +static void rpl_destroy_state(struct lwtunnel_state *lwt) +{ + dst_cache_destroy(&rpl_lwt_lwtunnel(lwt)->cache); +} + +static int rpl_do_srh_inline(struct sk_buff *skb, const struct rpl_lwt *rlwt, + const struct ipv6_rpl_sr_hdr *srh) +{ + struct ipv6_rpl_sr_hdr *isrh, *csrh; + const struct ipv6hdr *oldhdr; + struct ipv6hdr *hdr; + unsigned char *buf; + size_t hdrlen; + int err; + + oldhdr = ipv6_hdr(skb); + + buf = kcalloc(struct_size(srh, segments.addr, srh->segments_left), 2, GFP_ATOMIC); + if (!buf) + return -ENOMEM; + + isrh = (struct ipv6_rpl_sr_hdr *)buf; + csrh = (struct ipv6_rpl_sr_hdr *)(buf + ((srh->hdrlen + 1) << 3)); + + memcpy(isrh, srh, sizeof(*isrh)); + memcpy(isrh->rpl_segaddr, &srh->rpl_segaddr[1], + (srh->segments_left - 1) * 16); + isrh->rpl_segaddr[srh->segments_left - 1] = oldhdr->daddr; + + ipv6_rpl_srh_compress(csrh, isrh, &srh->rpl_segaddr[0], + isrh->segments_left - 1); + + hdrlen = ((csrh->hdrlen + 1) << 3); + + err = skb_cow_head(skb, hdrlen + skb->mac_len); + if (unlikely(err)) { + kfree(buf); + return err; + } + + skb_pull(skb, sizeof(struct ipv6hdr)); + skb_postpull_rcsum(skb, skb_network_header(skb), + sizeof(struct ipv6hdr)); + + skb_push(skb, sizeof(struct ipv6hdr) + hdrlen); + skb_reset_network_header(skb); + skb_mac_header_rebuild(skb); + + hdr = ipv6_hdr(skb); + memmove(hdr, oldhdr, sizeof(*hdr)); + isrh = (void *)hdr + sizeof(*hdr); + memcpy(isrh, csrh, hdrlen); + + isrh->nexthdr = hdr->nexthdr; + hdr->nexthdr = NEXTHDR_ROUTING; + hdr->daddr = srh->rpl_segaddr[0]; + + ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); + skb_set_transport_header(skb, sizeof(struct ipv6hdr)); + + skb_postpush_rcsum(skb, hdr, sizeof(struct ipv6hdr) + hdrlen); + + kfree(buf); + + return 0; +} + +static int rpl_do_srh(struct sk_buff *skb, const struct rpl_lwt *rlwt) +{ + struct dst_entry *dst = skb_dst(skb); + struct rpl_iptunnel_encap *tinfo; + int err = 0; + + if (skb->protocol != htons(ETH_P_IPV6)) + return -EINVAL; + + tinfo = rpl_encap_lwtunnel(dst->lwtstate); + + err = rpl_do_srh_inline(skb, rlwt, tinfo->srh); + if (err) + return err; + + return 0; +} + +static int rpl_output(struct net *net, struct sock *sk, struct sk_buff *skb) +{ + struct dst_entry *orig_dst = skb_dst(skb); + struct dst_entry *dst = NULL; + struct rpl_lwt *rlwt; + int err; + + rlwt = rpl_lwt_lwtunnel(orig_dst->lwtstate); + + err = rpl_do_srh(skb, rlwt); + if (unlikely(err)) + goto drop; + + preempt_disable(); + dst = dst_cache_get(&rlwt->cache); + preempt_enable(); + + if (unlikely(!dst)) { + struct ipv6hdr *hdr = ipv6_hdr(skb); + struct flowi6 fl6; + + memset(&fl6, 0, sizeof(fl6)); + fl6.daddr = hdr->daddr; + fl6.saddr = hdr->saddr; + fl6.flowlabel = ip6_flowinfo(hdr); + fl6.flowi6_mark = skb->mark; + fl6.flowi6_proto = hdr->nexthdr; + + dst = ip6_route_output(net, NULL, &fl6); + if (dst->error) { + err = dst->error; + dst_release(dst); + goto drop; + } + + preempt_disable(); + dst_cache_set_ip6(&rlwt->cache, dst, &fl6.saddr); + preempt_enable(); + } + + skb_dst_drop(skb); + skb_dst_set(skb, dst); + + err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); + if (unlikely(err)) + goto drop; + + return dst_output(net, sk, skb); + +drop: + kfree_skb(skb); + return err; +} + +static int rpl_input(struct sk_buff *skb) +{ + struct dst_entry *orig_dst = skb_dst(skb); + struct dst_entry *dst = NULL; + struct rpl_lwt *rlwt; + int err; + + rlwt = rpl_lwt_lwtunnel(orig_dst->lwtstate); + + err = rpl_do_srh(skb, rlwt); + if (unlikely(err)) { + kfree_skb(skb); + return err; + } + + preempt_disable(); + dst = dst_cache_get(&rlwt->cache); + preempt_enable(); + + skb_dst_drop(skb); + + if (!dst) { + ip6_route_input(skb); + dst = skb_dst(skb); + if (!dst->error) { + preempt_disable(); + dst_cache_set_ip6(&rlwt->cache, dst, + &ipv6_hdr(skb)->saddr); + preempt_enable(); + } + } else { + skb_dst_set(skb, dst); + } + + err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); + if (unlikely(err)) + return err; + + return dst_input(skb); +} + +static int nla_put_rpl_srh(struct sk_buff *skb, int attrtype, + struct rpl_iptunnel_encap *tuninfo) +{ + struct rpl_iptunnel_encap *data; + struct nlattr *nla; + int len; + + len = RPL_IPTUNNEL_SRH_SIZE(tuninfo->srh); + + nla = nla_reserve(skb, attrtype, len); + if (!nla) + return -EMSGSIZE; + + data = nla_data(nla); + memcpy(data, tuninfo->srh, len); + + return 0; +} + +static int rpl_fill_encap_info(struct sk_buff *skb, + struct lwtunnel_state *lwtstate) +{ + struct rpl_iptunnel_encap *tuninfo = rpl_encap_lwtunnel(lwtstate); + + if (nla_put_rpl_srh(skb, RPL_IPTUNNEL_SRH, tuninfo)) + return -EMSGSIZE; + + return 0; +} + +static int rpl_encap_nlsize(struct lwtunnel_state *lwtstate) +{ + struct rpl_iptunnel_encap *tuninfo = rpl_encap_lwtunnel(lwtstate); + + return nla_total_size(RPL_IPTUNNEL_SRH_SIZE(tuninfo->srh)); +} + +static int rpl_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b) +{ + struct rpl_iptunnel_encap *a_hdr = rpl_encap_lwtunnel(a); + struct rpl_iptunnel_encap *b_hdr = rpl_encap_lwtunnel(b); + int len = RPL_IPTUNNEL_SRH_SIZE(a_hdr->srh); + + if (len != RPL_IPTUNNEL_SRH_SIZE(b_hdr->srh)) + return 1; + + return memcmp(a_hdr, b_hdr, len); +} + +static const struct lwtunnel_encap_ops rpl_ops = { + .build_state = rpl_build_state, + .destroy_state = rpl_destroy_state, + .output = rpl_output, + .input = rpl_input, + .fill_encap = rpl_fill_encap_info, + .get_encap_size = rpl_encap_nlsize, + .cmp_encap = rpl_encap_cmp, + .owner = THIS_MODULE, +}; + +int __init rpl_init(void) +{ + int err; + + err = lwtunnel_encap_add_ops(&rpl_ops, LWTUNNEL_ENCAP_RPL); + if (err) + goto out; + + pr_info("RPL Segment Routing with IPv6\n"); + + return 0; + +out: + return err; +} + +void rpl_exit(void) +{ + lwtunnel_encap_del_ops(&rpl_ops, LWTUNNEL_ENCAP_RPL); +} |