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![Justin Iurman](/assets/img/avatar_default.png)
Add support for the IOAM insertion frequency inside its lwtunnel output function. This patch introduces a new (atomic) counter for packets, based on which the algorithm will decide if IOAM should be added or not. Default frequency is "1/1" (i.e., applied to all packets) for backward compatibility. The iproute2 patch is ready and will be submitted as soon as this one is accepted. Previous iproute2 command: ip -6 ro ad fc00::1/128 encap ioam6 [ mode ... ] ... New iproute2 command: ip -6 ro ad fc00::1/128 encap ioam6 [ freq k/n ] [ mode ... ] ... Signed-off-by: Justin Iurman <justin.iurman@uliege.be> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
477 lines
12 KiB
C
477 lines
12 KiB
C
// 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 <justin.iurman@uliege.be>
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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/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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#include <net/netlink.h>
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#include <net/ipv6.h>
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#include <net/dst_cache.h>
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#include <net/ip6_route.h>
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#include <net/addrconf.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_freq {
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u32 k;
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u32 n;
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};
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struct ioam6_lwt {
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struct dst_cache cache;
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struct ioam6_lwt_freq freq;
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atomic_t pkt_cnt;
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u8 mode;
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struct in6_addr tundst;
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struct ioam6_lwt_encap tuninfo;
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};
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static struct netlink_range_validation freq_range = {
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.min = IOAM6_IPTUNNEL_FREQ_MIN,
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.max = IOAM6_IPTUNNEL_FREQ_MAX,
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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_lwt_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_FREQ_K] = NLA_POLICY_FULL_RANGE(NLA_U32, &freq_range),
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[IOAM6_IPTUNNEL_FREQ_N] = NLA_POLICY_FULL_RANGE(NLA_U32, &freq_range),
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[IOAM6_IPTUNNEL_MODE] = NLA_POLICY_RANGE(NLA_U8,
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IOAM6_IPTUNNEL_MODE_MIN,
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IOAM6_IPTUNNEL_MODE_MAX),
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[IOAM6_IPTUNNEL_DST] = NLA_POLICY_EXACT_LEN(sizeof(struct in6_addr)),
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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 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 *lwt;
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struct ioam6_lwt *ilwt;
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int len_aligned, err;
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u32 freq_k, freq_n;
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u8 mode;
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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_FREQ_K] && tb[IOAM6_IPTUNNEL_FREQ_N]) ||
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(tb[IOAM6_IPTUNNEL_FREQ_K] && !tb[IOAM6_IPTUNNEL_FREQ_N])) {
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NL_SET_ERR_MSG(extack, "freq: missing parameter");
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return -EINVAL;
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} else if (!tb[IOAM6_IPTUNNEL_FREQ_K] && !tb[IOAM6_IPTUNNEL_FREQ_N]) {
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freq_k = IOAM6_IPTUNNEL_FREQ_MIN;
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freq_n = IOAM6_IPTUNNEL_FREQ_MIN;
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} else {
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freq_k = nla_get_u32(tb[IOAM6_IPTUNNEL_FREQ_K]);
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freq_n = nla_get_u32(tb[IOAM6_IPTUNNEL_FREQ_N]);
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if (freq_k > freq_n) {
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NL_SET_ERR_MSG(extack, "freq: k > n is forbidden");
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return -EINVAL;
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}
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}
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if (!tb[IOAM6_IPTUNNEL_MODE])
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mode = IOAM6_IPTUNNEL_MODE_INLINE;
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else
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mode = nla_get_u8(tb[IOAM6_IPTUNNEL_MODE]);
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if (!tb[IOAM6_IPTUNNEL_DST] && mode != IOAM6_IPTUNNEL_MODE_INLINE) {
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NL_SET_ERR_MSG(extack, "this mode needs a tunnel destination");
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return -EINVAL;
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}
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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_aligned = ALIGN(trace->remlen * 4, 8);
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lwt = lwtunnel_state_alloc(sizeof(*ilwt) + len_aligned);
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if (!lwt)
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return -ENOMEM;
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ilwt = ioam6_lwt_state(lwt);
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err = dst_cache_init(&ilwt->cache, GFP_ATOMIC);
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if (err) {
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kfree(lwt);
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return err;
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}
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atomic_set(&ilwt->pkt_cnt, 0);
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ilwt->freq.k = freq_k;
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ilwt->freq.n = freq_n;
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ilwt->mode = mode;
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if (tb[IOAM6_IPTUNNEL_DST])
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ilwt->tundst = nla_get_in6_addr(tb[IOAM6_IPTUNNEL_DST]);
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tuninfo = ioam6_lwt_info(lwt);
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tuninfo->eh.hdrlen = ((sizeof(*tuninfo) + 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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if (len_aligned - trace->remlen * 4) {
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tuninfo->traceh.data[trace->remlen * 4] = IPV6_TLV_PADN;
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tuninfo->traceh.data[trace->remlen * 4 + 1] = 2;
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}
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lwt->type = LWTUNNEL_ENCAP_IOAM6;
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lwt->flags |= LWTUNNEL_STATE_OUTPUT_REDIRECT;
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*ts = lwt;
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return 0;
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}
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static int ioam6_do_fill(struct net *net, struct sk_buff *skb)
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{
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struct ioam6_trace_hdr *trace;
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struct ioam6_namespace *ns;
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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(net, trace->namespace_id);
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if (ns)
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ioam6_fill_trace_data(skb, ns, trace, false);
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return 0;
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}
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static int ioam6_do_inline(struct net *net, struct sk_buff *skb,
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struct ioam6_lwt_encap *tuninfo)
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{
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struct ipv6hdr *oldhdr, *hdr;
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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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return ioam6_do_fill(net, skb);
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}
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static int ioam6_do_encap(struct net *net, struct sk_buff *skb,
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struct ioam6_lwt_encap *tuninfo,
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struct in6_addr *tundst)
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{
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struct dst_entry *dst = skb_dst(skb);
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struct ipv6hdr *hdr, *inner_hdr;
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int hdrlen, len, err;
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hdrlen = (tuninfo->eh.hdrlen + 1) << 3;
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len = sizeof(*hdr) + hdrlen;
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err = skb_cow_head(skb, len + skb->mac_len);
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if (unlikely(err))
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return err;
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inner_hdr = ipv6_hdr(skb);
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skb_push(skb, len);
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skb_reset_network_header(skb);
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skb_mac_header_rebuild(skb);
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skb_set_transport_header(skb, sizeof(*hdr));
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tuninfo->eh.nexthdr = NEXTHDR_IPV6;
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memcpy(skb_transport_header(skb), (u8 *)tuninfo, hdrlen);
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hdr = ipv6_hdr(skb);
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memcpy(hdr, inner_hdr, sizeof(*hdr));
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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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hdr->daddr = *tundst;
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ipv6_dev_get_saddr(net, dst->dev, &hdr->daddr,
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IPV6_PREFER_SRC_PUBLIC, &hdr->saddr);
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skb_postpush_rcsum(skb, hdr, len);
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return ioam6_do_fill(net, skb);
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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 dst_entry *dst = skb_dst(skb);
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struct in6_addr orig_daddr;
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struct ioam6_lwt *ilwt;
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int err = -EINVAL;
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u32 pkt_cnt;
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if (skb->protocol != htons(ETH_P_IPV6))
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goto drop;
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ilwt = ioam6_lwt_state(dst->lwtstate);
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/* Check for insertion frequency (i.e., "k over n" insertions) */
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pkt_cnt = atomic_fetch_inc(&ilwt->pkt_cnt);
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if (pkt_cnt % ilwt->freq.n >= ilwt->freq.k)
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goto out;
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orig_daddr = ipv6_hdr(skb)->daddr;
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switch (ilwt->mode) {
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case IOAM6_IPTUNNEL_MODE_INLINE:
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do_inline:
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/* Direct insertion - if there is no Hop-by-Hop yet */
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if (ipv6_hdr(skb)->nexthdr == NEXTHDR_HOP)
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goto out;
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err = ioam6_do_inline(net, skb, &ilwt->tuninfo);
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if (unlikely(err))
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goto drop;
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break;
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case IOAM6_IPTUNNEL_MODE_ENCAP:
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do_encap:
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/* Encapsulation (ip6ip6) */
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err = ioam6_do_encap(net, skb, &ilwt->tuninfo, &ilwt->tundst);
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if (unlikely(err))
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goto drop;
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break;
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case IOAM6_IPTUNNEL_MODE_AUTO:
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/* Automatic (RFC8200 compliant):
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* - local packets -> INLINE mode
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* - in-transit packets -> ENCAP mode
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*/
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if (!skb->dev)
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goto do_inline;
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goto do_encap;
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default:
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goto drop;
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}
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err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
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if (unlikely(err))
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goto drop;
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if (!ipv6_addr_equal(&orig_daddr, &ipv6_hdr(skb)->daddr)) {
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preempt_disable();
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dst = dst_cache_get(&ilwt->cache);
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preempt_enable();
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if (unlikely(!dst)) {
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struct ipv6hdr *hdr = ipv6_hdr(skb);
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struct flowi6 fl6;
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memset(&fl6, 0, sizeof(fl6));
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fl6.daddr = hdr->daddr;
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fl6.saddr = hdr->saddr;
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fl6.flowlabel = ip6_flowinfo(hdr);
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fl6.flowi6_mark = skb->mark;
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fl6.flowi6_proto = hdr->nexthdr;
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dst = ip6_route_output(net, NULL, &fl6);
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if (dst->error) {
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err = dst->error;
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dst_release(dst);
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goto drop;
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}
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preempt_disable();
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dst_cache_set_ip6(&ilwt->cache, dst, &fl6.saddr);
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preempt_enable();
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}
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skb_dst_drop(skb);
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skb_dst_set(skb, dst);
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return dst_output(net, sk, skb);
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}
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out:
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return dst->lwtstate->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 void ioam6_destroy_state(struct lwtunnel_state *lwt)
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{
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dst_cache_destroy(&ioam6_lwt_state(lwt)->cache);
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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_lwt *ilwt = ioam6_lwt_state(lwtstate);
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int err;
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err = nla_put_u32(skb, IOAM6_IPTUNNEL_FREQ_K, ilwt->freq.k);
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if (err)
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goto ret;
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err = nla_put_u32(skb, IOAM6_IPTUNNEL_FREQ_N, ilwt->freq.n);
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if (err)
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goto ret;
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err = nla_put_u8(skb, IOAM6_IPTUNNEL_MODE, ilwt->mode);
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if (err)
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goto ret;
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if (ilwt->mode != IOAM6_IPTUNNEL_MODE_INLINE) {
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err = nla_put_in6_addr(skb, IOAM6_IPTUNNEL_DST, &ilwt->tundst);
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if (err)
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goto ret;
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}
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err = nla_put(skb, IOAM6_IPTUNNEL_TRACE, sizeof(ilwt->tuninfo.traceh),
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&ilwt->tuninfo.traceh);
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ret:
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return err;
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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_lwt *ilwt = ioam6_lwt_state(lwtstate);
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int nlsize;
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nlsize = nla_total_size(sizeof(ilwt->freq.k)) +
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nla_total_size(sizeof(ilwt->freq.n)) +
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nla_total_size(sizeof(ilwt->mode)) +
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nla_total_size(sizeof(ilwt->tuninfo.traceh));
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if (ilwt->mode != IOAM6_IPTUNNEL_MODE_INLINE)
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nlsize += nla_total_size(sizeof(ilwt->tundst));
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return nlsize;
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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 *trace_a = ioam6_lwt_trace(a);
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struct ioam6_trace_hdr *trace_b = ioam6_lwt_trace(b);
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struct ioam6_lwt *ilwt_a = ioam6_lwt_state(a);
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struct ioam6_lwt *ilwt_b = ioam6_lwt_state(b);
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return (ilwt_a->freq.k != ilwt_b->freq.k ||
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ilwt_a->freq.n != ilwt_b->freq.n ||
|
|
ilwt_a->mode != ilwt_b->mode ||
|
|
(ilwt_a->mode != IOAM6_IPTUNNEL_MODE_INLINE &&
|
|
!ipv6_addr_equal(&ilwt_a->tundst, &ilwt_b->tundst)) ||
|
|
trace_a->namespace_id != trace_b->namespace_id);
|
|
}
|
|
|
|
static const struct lwtunnel_encap_ops ioam6_iptun_ops = {
|
|
.build_state = ioam6_build_state,
|
|
.destroy_state = ioam6_destroy_state,
|
|
.output = ioam6_output,
|
|
.fill_encap = ioam6_fill_encap_info,
|
|
.get_encap_size = ioam6_encap_nlsize,
|
|
.cmp_encap = ioam6_encap_cmp,
|
|
.owner = THIS_MODULE,
|
|
};
|
|
|
|
int __init ioam6_iptunnel_init(void)
|
|
{
|
|
return lwtunnel_encap_add_ops(&ioam6_iptun_ops, LWTUNNEL_ENCAP_IOAM6);
|
|
}
|
|
|
|
void ioam6_iptunnel_exit(void)
|
|
{
|
|
lwtunnel_encap_del_ops(&ioam6_iptun_ops, LWTUNNEL_ENCAP_IOAM6);
|
|
}
|