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278 lines
6.7 KiB
278 lines
6.7 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* IPv6 IOAM Lightweight Tunnel implementation |
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* |
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* Author: |
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* Justin Iurman <[email protected]> |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/skbuff.h> |
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#include <linux/net.h> |
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#include <linux/netlink.h> |
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#include <linux/in6.h> |
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#include <linux/ioam6.h> |
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#include <linux/ioam6_iptunnel.h> |
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#include <net/dst.h> |
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#include <net/sock.h> |
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#include <net/lwtunnel.h> |
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#include <net/ioam6.h> |
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#define IOAM6_MASK_SHORT_FIELDS 0xff100000 |
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#define IOAM6_MASK_WIDE_FIELDS 0xe00000 |
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struct ioam6_lwt_encap { |
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struct ipv6_hopopt_hdr eh; |
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u8 pad[2]; /* 2-octet padding for 4n-alignment */ |
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struct ioam6_hdr ioamh; |
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struct ioam6_trace_hdr traceh; |
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} __packed; |
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struct ioam6_lwt { |
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struct ioam6_lwt_encap tuninfo; |
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}; |
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static struct ioam6_lwt *ioam6_lwt_state(struct lwtunnel_state *lwt) |
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{ |
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return (struct ioam6_lwt *)lwt->data; |
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} |
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static struct ioam6_lwt_encap *ioam6_lwt_info(struct lwtunnel_state *lwt) |
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{ |
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return &ioam6_lwt_state(lwt)->tuninfo; |
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} |
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static struct ioam6_trace_hdr *ioam6_trace(struct lwtunnel_state *lwt) |
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{ |
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return &(ioam6_lwt_state(lwt)->tuninfo.traceh); |
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} |
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static const struct nla_policy ioam6_iptunnel_policy[IOAM6_IPTUNNEL_MAX + 1] = { |
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[IOAM6_IPTUNNEL_TRACE] = NLA_POLICY_EXACT_LEN(sizeof(struct ioam6_trace_hdr)), |
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}; |
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static int nla_put_ioam6_trace(struct sk_buff *skb, int attrtype, |
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struct ioam6_trace_hdr *trace) |
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{ |
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struct ioam6_trace_hdr *data; |
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struct nlattr *nla; |
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int len; |
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len = sizeof(*trace); |
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nla = nla_reserve(skb, attrtype, len); |
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if (!nla) |
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return -EMSGSIZE; |
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data = nla_data(nla); |
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memcpy(data, trace, len); |
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return 0; |
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} |
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static bool ioam6_validate_trace_hdr(struct ioam6_trace_hdr *trace) |
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{ |
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u32 fields; |
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if (!trace->type_be32 || !trace->remlen || |
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trace->remlen > IOAM6_TRACE_DATA_SIZE_MAX / 4 || |
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trace->type.bit12 | trace->type.bit13 | trace->type.bit14 | |
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trace->type.bit15 | trace->type.bit16 | trace->type.bit17 | |
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trace->type.bit18 | trace->type.bit19 | trace->type.bit20 | |
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trace->type.bit21) |
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return false; |
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trace->nodelen = 0; |
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fields = be32_to_cpu(trace->type_be32); |
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trace->nodelen += hweight32(fields & IOAM6_MASK_SHORT_FIELDS) |
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* (sizeof(__be32) / 4); |
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trace->nodelen += hweight32(fields & IOAM6_MASK_WIDE_FIELDS) |
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* (sizeof(__be64) / 4); |
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return true; |
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} |
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static int ioam6_build_state(struct net *net, struct nlattr *nla, |
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unsigned int family, const void *cfg, |
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struct lwtunnel_state **ts, |
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struct netlink_ext_ack *extack) |
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{ |
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struct nlattr *tb[IOAM6_IPTUNNEL_MAX + 1]; |
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struct ioam6_lwt_encap *tuninfo; |
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struct ioam6_trace_hdr *trace; |
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struct lwtunnel_state *s; |
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int len_aligned; |
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int len, err; |
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if (family != AF_INET6) |
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return -EINVAL; |
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err = nla_parse_nested(tb, IOAM6_IPTUNNEL_MAX, nla, |
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ioam6_iptunnel_policy, extack); |
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if (err < 0) |
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return err; |
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if (!tb[IOAM6_IPTUNNEL_TRACE]) { |
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NL_SET_ERR_MSG(extack, "missing trace"); |
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return -EINVAL; |
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} |
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trace = nla_data(tb[IOAM6_IPTUNNEL_TRACE]); |
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if (!ioam6_validate_trace_hdr(trace)) { |
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NL_SET_ERR_MSG_ATTR(extack, tb[IOAM6_IPTUNNEL_TRACE], |
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"invalid trace validation"); |
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return -EINVAL; |
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} |
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len = sizeof(*tuninfo) + trace->remlen * 4; |
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len_aligned = ALIGN(len, 8); |
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s = lwtunnel_state_alloc(len_aligned); |
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if (!s) |
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return -ENOMEM; |
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tuninfo = ioam6_lwt_info(s); |
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tuninfo->eh.hdrlen = (len_aligned >> 3) - 1; |
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tuninfo->pad[0] = IPV6_TLV_PADN; |
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tuninfo->ioamh.type = IOAM6_TYPE_PREALLOC; |
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tuninfo->ioamh.opt_type = IPV6_TLV_IOAM; |
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tuninfo->ioamh.opt_len = sizeof(tuninfo->ioamh) - 2 + sizeof(*trace) |
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+ trace->remlen * 4; |
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memcpy(&tuninfo->traceh, trace, sizeof(*trace)); |
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len = len_aligned - len; |
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if (len == 1) { |
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tuninfo->traceh.data[trace->remlen * 4] = IPV6_TLV_PAD1; |
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} else if (len > 0) { |
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tuninfo->traceh.data[trace->remlen * 4] = IPV6_TLV_PADN; |
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tuninfo->traceh.data[trace->remlen * 4 + 1] = len - 2; |
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} |
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s->type = LWTUNNEL_ENCAP_IOAM6; |
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s->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT; |
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*ts = s; |
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return 0; |
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} |
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static int ioam6_do_inline(struct sk_buff *skb, struct ioam6_lwt_encap *tuninfo) |
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{ |
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struct ioam6_trace_hdr *trace; |
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struct ipv6hdr *oldhdr, *hdr; |
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struct ioam6_namespace *ns; |
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int hdrlen, err; |
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hdrlen = (tuninfo->eh.hdrlen + 1) << 3; |
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err = skb_cow_head(skb, hdrlen + skb->mac_len); |
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if (unlikely(err)) |
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return err; |
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oldhdr = ipv6_hdr(skb); |
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skb_pull(skb, sizeof(*oldhdr)); |
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skb_postpull_rcsum(skb, skb_network_header(skb), sizeof(*oldhdr)); |
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skb_push(skb, sizeof(*oldhdr) + hdrlen); |
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skb_reset_network_header(skb); |
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skb_mac_header_rebuild(skb); |
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hdr = ipv6_hdr(skb); |
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memmove(hdr, oldhdr, sizeof(*oldhdr)); |
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tuninfo->eh.nexthdr = hdr->nexthdr; |
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skb_set_transport_header(skb, sizeof(*hdr)); |
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skb_postpush_rcsum(skb, hdr, sizeof(*hdr) + hdrlen); |
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memcpy(skb_transport_header(skb), (u8 *)tuninfo, hdrlen); |
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hdr->nexthdr = NEXTHDR_HOP; |
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hdr->payload_len = cpu_to_be16(skb->len - sizeof(*hdr)); |
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trace = (struct ioam6_trace_hdr *)(skb_transport_header(skb) |
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+ sizeof(struct ipv6_hopopt_hdr) + 2 |
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+ sizeof(struct ioam6_hdr)); |
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ns = ioam6_namespace(dev_net(skb_dst(skb)->dev), trace->namespace_id); |
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if (ns) |
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ioam6_fill_trace_data(skb, ns, trace); |
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return 0; |
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} |
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static int ioam6_output(struct net *net, struct sock *sk, struct sk_buff *skb) |
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{ |
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struct lwtunnel_state *lwt = skb_dst(skb)->lwtstate; |
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int err = -EINVAL; |
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if (skb->protocol != htons(ETH_P_IPV6)) |
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goto drop; |
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/* Only for packets we send and |
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* that do not contain a Hop-by-Hop yet |
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*/ |
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if (skb->dev || ipv6_hdr(skb)->nexthdr == NEXTHDR_HOP) |
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goto out; |
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err = ioam6_do_inline(skb, ioam6_lwt_info(lwt)); |
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if (unlikely(err)) |
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goto drop; |
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err = skb_cow_head(skb, LL_RESERVED_SPACE(skb_dst(skb)->dev)); |
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if (unlikely(err)) |
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goto drop; |
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out: |
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return lwt->orig_output(net, sk, skb); |
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drop: |
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kfree_skb(skb); |
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return err; |
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} |
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static int ioam6_fill_encap_info(struct sk_buff *skb, |
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struct lwtunnel_state *lwtstate) |
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{ |
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struct ioam6_trace_hdr *trace = ioam6_trace(lwtstate); |
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if (nla_put_ioam6_trace(skb, IOAM6_IPTUNNEL_TRACE, trace)) |
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return -EMSGSIZE; |
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return 0; |
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} |
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static int ioam6_encap_nlsize(struct lwtunnel_state *lwtstate) |
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{ |
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struct ioam6_trace_hdr *trace = ioam6_trace(lwtstate); |
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return nla_total_size(sizeof(*trace)); |
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} |
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static int ioam6_encap_cmp(struct lwtunnel_state *a, struct lwtunnel_state *b) |
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{ |
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struct ioam6_trace_hdr *a_hdr = ioam6_trace(a); |
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struct ioam6_trace_hdr *b_hdr = ioam6_trace(b); |
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return (a_hdr->namespace_id != b_hdr->namespace_id); |
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} |
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static const struct lwtunnel_encap_ops ioam6_iptun_ops = { |
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.build_state = ioam6_build_state, |
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.output = ioam6_output, |
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.fill_encap = ioam6_fill_encap_info, |
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.get_encap_size = ioam6_encap_nlsize, |
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.cmp_encap = ioam6_encap_cmp, |
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.owner = THIS_MODULE, |
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}; |
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int __init ioam6_iptunnel_init(void) |
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{ |
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return lwtunnel_encap_add_ops(&ioam6_iptun_ops, LWTUNNEL_ENCAP_IOAM6); |
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} |
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void ioam6_iptunnel_exit(void) |
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{ |
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lwtunnel_encap_del_ops(&ioam6_iptun_ops, LWTUNNEL_ENCAP_IOAM6); |
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}
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