sd-icmp6-nd: Parse ICMPv6 prefix information
Save each new onlink IPv6 prefix and attach an expiry timer to it. If the prefixes overlap, take the shorter prefix and write a debug message about the event. Once the prefix is resent in a Router Advertisement, update the timer. Add a new event for the expiring prefix. Add two helper functions, one for returning a prefix length given a Router Advertisement and the other for generic prefix matching given an IPv6 prefix and address.
This commit is contained in:
Patrik Flykt
parent
8d7f2c6a47
commit
d77bde34cf
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@ -249,6 +249,201 @@ int sd_icmp6_ra_get_mtu(sd_icmp6_nd *nd, uint32_t *mtu) {
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return 0;
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}
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static int icmp6_ra_prefix_timeout(sd_event_source *s, uint64_t usec,
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void *userdata) {
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sd_icmp6_nd *nd = userdata;
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ICMP6Prefix *prefix, *p;
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assert(nd);
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LIST_FOREACH_SAFE(prefixes, prefix, p, nd->prefixes) {
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if (prefix->timeout_valid != s)
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continue;
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log_icmp6_nd(nd, "Prefix expired "SD_ICMP6_ADDRESS_FORMAT_STR"/%d",
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SD_ICMP6_ADDRESS_FORMAT_VAL(prefix->addr),
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prefix->len);
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LIST_REMOVE(prefixes, nd->prefixes, prefix);
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icmp6_nd_notify(nd,
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ICMP6_EVENT_ROUTER_ADVERTISMENT_PREFIX_EXPIRED);
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prefix = icmp6_prefix_unref(prefix);
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break;
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}
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return 0;
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}
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static int icmp6_ra_prefix_set_timeout(sd_icmp6_nd *nd,
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ICMP6Prefix *prefix,
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usec_t valid) {
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usec_t time_now;
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int r;
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assert_return(prefix, -EINVAL);
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r = sd_event_now(nd->event, clock_boottime_or_monotonic(), &time_now);
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if (r < 0)
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return r;
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prefix->timeout_valid = sd_event_source_unref(prefix->timeout_valid);
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r = sd_event_add_time(nd->event, &prefix->timeout_valid,
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clock_boottime_or_monotonic(), time_now + valid,
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USEC_PER_SEC, icmp6_ra_prefix_timeout, nd);
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if (r < 0)
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goto error;
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r = sd_event_source_set_priority(prefix->timeout_valid,
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nd->event_priority);
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if (r < 0)
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goto error;
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r = sd_event_source_set_description(prefix->timeout_valid,
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"icmp6-prefix-timeout");
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error:
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if (r < 0)
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prefix->timeout_valid =
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sd_event_source_unref(prefix->timeout_valid);
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return r;
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}
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static int icmp6_prefix_match(const struct in6_addr *prefix, uint8_t prefixlen,
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const struct in6_addr *addr,
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uint8_t addr_prefixlen) {
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uint8_t bytes, mask, len;
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assert_return(prefix, -EINVAL);
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assert_return(addr, -EINVAL);
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len = MIN(prefixlen, addr_prefixlen);
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bytes = len / 8;
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mask = 0xff << (8 - len % 8);
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if (memcmp(prefix, addr, bytes) != 0 ||
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(prefix->s6_addr[bytes] & mask) != (addr->s6_addr[bytes] & mask))
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return -EADDRNOTAVAIL;
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return 0;
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}
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static int icmp6_ra_prefix_match(ICMP6Prefix *head, const struct in6_addr *addr,
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uint8_t addr_len, ICMP6Prefix **result) {
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ICMP6Prefix *prefix;
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LIST_FOREACH(prefixes, prefix, head) {
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if (icmp6_prefix_match(&prefix->addr, prefix->len, addr,
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addr_len) >= 0) {
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*result = prefix;
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return 0;
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}
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}
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return -EADDRNOTAVAIL;
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}
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int sd_icmp6_prefix_match(struct in6_addr *prefix, uint8_t prefixlen,
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struct in6_addr *addr) {
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return icmp6_prefix_match(prefix, prefixlen, addr,
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sizeof(addr->s6_addr) * 8);
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}
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int sd_icmp6_ra_get_prefixlen(sd_icmp6_nd *nd, const struct in6_addr *addr,
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uint8_t *prefixlen) {
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int r;
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ICMP6Prefix *prefix;
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assert_return(nd, -EINVAL);
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assert_return(addr, -EINVAL);
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assert_return(prefixlen, -EINVAL);
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r = icmp6_ra_prefix_match(nd->prefixes, addr,
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sizeof(addr->s6_addr) * 8, &prefix);
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if (r < 0)
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return r;
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*prefixlen = prefix->len;
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return 0;
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}
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static int icmp6_ra_prefix_update(sd_icmp6_nd *nd, ssize_t len,
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const struct nd_opt_prefix_info *prefix_opt) {
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int r;
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ICMP6Prefix *prefix;
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uint32_t lifetime;
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char time_string[FORMAT_TIMESPAN_MAX];
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assert_return(nd, -EINVAL);
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assert_return(prefix_opt, -EINVAL);
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if (len < prefix_opt->nd_opt_pi_len)
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return -ENOMSG;
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if (!(prefix_opt->nd_opt_pi_flags_reserved & ND_OPT_PI_FLAG_ONLINK))
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return 0;
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lifetime = be32toh(prefix_opt->nd_opt_pi_valid_time);
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r = icmp6_ra_prefix_match(nd->prefixes,
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&prefix_opt->nd_opt_pi_prefix,
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prefix_opt->nd_opt_pi_prefix_len, &prefix);
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if (r < 0 && r != -EADDRNOTAVAIL)
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return r;
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/* if router advertisment prefix valid timeout is zero, the timeout
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callback will be called immediately to clean up the prefix */
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if (r == -EADDRNOTAVAIL) {
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r = icmp6_prefix_new(&prefix);
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if (r < 0)
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return r;
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prefix->len = prefix_opt->nd_opt_pi_prefix_len;
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memcpy(&prefix->addr, &prefix_opt->nd_opt_pi_prefix,
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sizeof(prefix->addr));
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log_icmp6_nd(nd, "New prefix "SD_ICMP6_ADDRESS_FORMAT_STR"/%d lifetime %d expires in %s",
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SD_ICMP6_ADDRESS_FORMAT_VAL(prefix->addr),
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prefix->len, lifetime,
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format_timespan(time_string, FORMAT_TIMESPAN_MAX,
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lifetime * USEC_PER_SEC, 0));
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LIST_PREPEND(prefixes, nd->prefixes, prefix);
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} else {
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if (prefix->len != prefix_opt->nd_opt_pi_prefix_len) {
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uint8_t prefixlen;
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prefixlen = MIN(prefix->len, prefix_opt->nd_opt_pi_prefix_len);
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log_icmp6_nd(nd, "Prefix length mismatch %d/%d using %d",
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prefix->len,
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prefix_opt->nd_opt_pi_prefix_len,
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prefixlen);
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prefix->len = prefixlen;
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}
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log_icmp6_nd(nd, "Update prefix "SD_ICMP6_ADDRESS_FORMAT_STR"/%d lifetime %d expires in %s",
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SD_ICMP6_ADDRESS_FORMAT_VAL(prefix->addr),
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prefix->len, lifetime,
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format_timespan(time_string, FORMAT_TIMESPAN_MAX,
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lifetime * USEC_PER_SEC, 0));
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}
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r = icmp6_ra_prefix_set_timeout(nd, prefix, lifetime * USEC_PER_SEC);
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return r;
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}
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static int icmp6_ra_parse(sd_icmp6_nd *nd, struct nd_router_advert *ra,
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ssize_t len) {
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void *opt;
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@ -270,6 +465,7 @@ static int icmp6_ra_parse(sd_icmp6_nd *nd, struct nd_router_advert *ra,
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while (len != 0 && len >= opt_hdr->nd_opt_len * ICMP6_OPT_LEN_UNITS) {
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struct nd_opt_mtu *opt_mtu;
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uint32_t mtu;
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struct nd_opt_prefix_info *opt_prefix;
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if (opt_hdr->nd_opt_len == 0)
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return -ENOMSG;
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@ -289,6 +485,12 @@ static int icmp6_ra_parse(sd_icmp6_nd *nd, struct nd_router_advert *ra,
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break;
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case ND_OPT_PREFIX_INFORMATION:
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opt_prefix = opt;
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icmp6_ra_prefix_update(nd, len, opt_prefix);
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break;
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}
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len -= opt_hdr->nd_opt_len * ICMP6_OPT_LEN_UNITS;
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@ -27,10 +27,11 @@
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#include "sd-event.h"
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enum {
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ICMP6_EVENT_ROUTER_ADVERTISMENT_NONE = 0,
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ICMP6_EVENT_ROUTER_ADVERTISMENT_TIMEOUT = 1,
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ICMP6_EVENT_ROUTER_ADVERTISMENT_OTHER = 2,
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ICMP6_EVENT_ROUTER_ADVERTISMENT_MANAGED = 3,
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ICMP6_EVENT_ROUTER_ADVERTISMENT_NONE = 0,
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ICMP6_EVENT_ROUTER_ADVERTISMENT_TIMEOUT = 1,
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ICMP6_EVENT_ROUTER_ADVERTISMENT_OTHER = 2,
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ICMP6_EVENT_ROUTER_ADVERTISMENT_MANAGED = 3,
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ICMP6_EVENT_ROUTER_ADVERTISMENT_PREFIX_EXPIRED = 4,
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};
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typedef struct sd_icmp6_nd sd_icmp6_nd;
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@ -51,9 +52,26 @@ sd_icmp6_nd *sd_icmp6_nd_ref(sd_icmp6_nd *nd);
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sd_icmp6_nd *sd_icmp6_nd_unref(sd_icmp6_nd *nd);
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int sd_icmp6_nd_new(sd_icmp6_nd **ret);
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int sd_icmp6_prefix_match(struct in6_addr *prefix, uint8_t prefixlen,
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struct in6_addr *addr);
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int sd_icmp6_ra_get_mtu(sd_icmp6_nd *nd, uint32_t *mtu);
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int sd_icmp6_ra_get_prefixlen(sd_icmp6_nd *nd, const struct in6_addr *addr,
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uint8_t *prefixlen);
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int sd_icmp6_nd_stop(sd_icmp6_nd *nd);
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int sd_icmp6_router_solicitation_start(sd_icmp6_nd *nd);
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#define SD_ICMP6_ADDRESS_FORMAT_STR "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x"
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#define SD_ICMP6_ADDRESS_FORMAT_VAL(address) \
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be16toh((address).s6_addr16[0]), \
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be16toh((address).s6_addr16[1]), \
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be16toh((address).s6_addr16[2]), \
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be16toh((address).s6_addr16[3]), \
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be16toh((address).s6_addr16[4]), \
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be16toh((address).s6_addr16[5]), \
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be16toh((address).s6_addr16[6]), \
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be16toh((address).s6_addr16[7])
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#endif
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