[systemd-devel] [PATCH 07/11] sd-icmp6-nd: Parse ICMPv6 prefix information
Zbigniew Jędrzejewski-Szmek
zbyszek at in.waw.pl
Tue Jan 13 16:26:51 PST 2015
On Tue, Jan 13, 2015 at 02:02:17PM +0200, Patrik Flykt wrote:
> 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.
> ---
> src/libsystemd-network/sd-icmp6-nd.c | 222 +++++++++++++++++++++++++++++++++++
> src/systemd/sd-icmp6-nd.h | 6 +
> 2 files changed, 228 insertions(+)
>
> diff --git a/src/libsystemd-network/sd-icmp6-nd.c b/src/libsystemd-network/sd-icmp6-nd.c
> index 3501055..4848912 100644
> --- a/src/libsystemd-network/sd-icmp6-nd.c
> +++ b/src/libsystemd-network/sd-icmp6-nd.c
> @@ -283,11 +283,227 @@ int sd_icmp6_ra_get_mtu(sd_icmp6_nd *nd, uint32_t *mtu) {
> return 0;
> }
>
> +static int icmp6_ra_prefix_timeout(sd_event_source *s, uint64_t usec,
> + void *userdata) {
Indentation, here and below too.
> + sd_icmp6_nd *nd = userdata;
> + struct icmp6_prefix *prefix, *p;
> +
> + assert(nd);
> + assert(nd->link);
> + assert(nd->link->prefixes);
> +
> + LIST_FOREACH_SAFE(prefixes, prefix, p, nd->link->prefixes) {
> + if (prefix->timeout_valid != s)
> + continue;
> +
> + log_icmp6_nd(nd, "Prefix expired %02x%02x:%02x%02x:%02x%02x:%02x%02x/%d",
> + prefix->addr.s6_addr[0], prefix->addr.s6_addr[1],
> + prefix->addr.s6_addr[2], prefix->addr.s6_addr[3],
> + prefix->addr.s6_addr[4], prefix->addr.s6_addr[5],
> + prefix->addr.s6_addr[6], prefix->addr.s6_addr[7],
> + prefix->len);
> +
> + LIST_REMOVE(prefixes, nd->link->prefixes, prefix);
> +
> + icmp6_nd_notify(nd,
> + ICMP6_EVENT_ROUTER_ADVERTISMENT_PREFIX_EXPIRED);
> + prefix = icmp6_prefix_unref(prefix);
> +
> + break;
> + }
> +
> + return 0;
> +}
> +
> +static int icmp6_ra_prefix_set_timeout(sd_icmp6_nd *nd,
> + struct icmp6_prefix *prefix, usec_t valid) {
> + usec_t time_now;
> + int r;
> +
> + assert_return(prefix, -EINVAL);
> +
> + r = sd_event_now(nd->event, clock_boottime_or_monotonic(), &time_now);
> + if (r < 0)
> + return r;
> +
> + prefix->timeout_valid = sd_event_source_unref(prefix->timeout_valid);
> +
> + r = sd_event_add_time(nd->event, &prefix->timeout_valid,
> + clock_boottime_or_monotonic(), time_now + valid,
> + USEC_PER_SEC, icmp6_ra_prefix_timeout, nd);
> + if (r < 0)
> + goto error;
> +
> + r = sd_event_source_set_priority(prefix->timeout_valid,
> + nd->event_priority);
> + if (r < 0)
> + goto error;
> +
> + r = sd_event_source_set_description(prefix->timeout_valid,
> + "icmp6-prefix-timeout");
> +
> +error:
> + if (r < 0)
> + prefix->timeout_valid =
> + sd_event_source_unref(prefix->timeout_valid);
> +
> + return r;
> +}
> +
> +static int icmp6_prefix_match(const struct in6_addr *prefix, uint8_t prefixlen,
> + const struct in6_addr *addr, uint8_t addr_prefixlen) {
> + uint8_t bytes, mask, len;
> +
> + assert_return(prefix, -EINVAL);
> + assert_return(addr, -EINVAL);
> +
> + len = (prefixlen < addr_prefixlen)? prefixlen: addr_prefixlen;
MIN()
> +
> + bytes = len / 8;
> +
> + if (memcmp(prefix, addr, bytes))
> + return -EADDRNOTAVAIL;
> +
> + if (len % 8) {
I guess you can just remove the if() and say
mask = 0xff << (8 - len % 8);
if (memcmp(prefix, addr, bytes) != 0 ||
(prefix->s6_addr[bytes] & mask) != (addr->s6_addr[bytes] & mask))
return ...;
> +
> +
> + if ((prefix->s6_addr[bytes] & mask) !=
> + (addr->s6_addr[bytes] & mask))
> + return -EADDRNOTAVAIL;
> + }
> +
> + return 0;
> +}
> +
> +static int icmp6_ra_prefix_match(struct icmp6_prefix *head,
> + const struct in6_addr *addr, uint8_t addr_len,
> + struct icmp6_prefix **result) {
> + struct icmp6_prefix *prefix;
> +
> + LIST_FOREACH(prefixes, prefix, head) {
> + if (icmp6_prefix_match(&prefix->addr, prefix->len, addr,
> + addr_len) >= 0) {
> + *result = prefix;
> + return 0;
> + }
> + }
> +
> + return -EADDRNOTAVAIL;
> +}
> +
> +int sd_icmp6_prefix_match(struct in6_addr *prefix, uint8_t prefixlen,
> + struct in6_addr *addr) {
> + return icmp6_prefix_match(prefix, prefixlen, addr,
> + sizeof(addr->s6_addr) * 8);
> +}
> +
> +int sd_icmp6_ra_get_prefixlen(sd_icmp6_nd *nd, const struct in6_addr *addr,
> + uint8_t *prefixlen) {
> + int r;
> + struct icmp6_prefix *prefix;
> +
> + assert_return(nd, -EINVAL);
> + assert_return(addr, -EINVAL);
> + assert_return(prefixlen, -EINVAL);
> +
> + if (!nd->link)
> + return -EADDRNOTAVAIL;
> +
> + r = icmp6_ra_prefix_match(nd->link->prefixes, addr,
> + sizeof(addr->s6_addr) * 8, &prefix);
> + if (r < 0)
> + return r;
> +
> + *prefixlen = prefix->len;
> +
> + return 0;
> +}
> +
> +static int icmp6_ra_prefix_update(sd_icmp6_nd *nd, ssize_t len,
> + const struct nd_opt_prefix_info *prefix_opt) {
> + int r;
> + struct icmp6_prefix *prefix;
> + uint32_t lifetime;
> + char time_string[FORMAT_TIMESPAN_MAX];
> +
> + assert_return(nd, -EINVAL);
> + assert_return(nd->link, -EINVAL);
> + assert_return(prefix_opt, -EINVAL);
> +
> + if (len < prefix_opt->nd_opt_pi_len)
> + return -ENOMSG;
> +
> + if (!(prefix_opt->nd_opt_pi_flags_reserved & ND_OPT_PI_FLAG_ONLINK))
> + return 0;
> +
> + lifetime = be32toh(prefix_opt->nd_opt_pi_valid_time);
> +
> + r = icmp6_ra_prefix_match(nd->link->prefixes,
> + &prefix_opt->nd_opt_pi_prefix,
> + prefix_opt->nd_opt_pi_prefix_len, &prefix);
> +
> + if (r < 0 && r != -EADDRNOTAVAIL)
> + return r;
> +
> + /* if router advertisment prefix valid timeout is zero, the timeout
> + callback will be called immediately to clean up the prefix */
> +
> + if (r == -EADDRNOTAVAIL) {
> + r = icmp6_prefix_new(&prefix);
> + if (r < 0)
> + return r;
> +
> + prefix->len = prefix_opt->nd_opt_pi_prefix_len;
> +
> + memcpy(&prefix->addr, &prefix_opt->nd_opt_pi_prefix,
> + sizeof(prefix->addr));
> +
> + log_icmp6_nd(nd, "New prefix %02x%02x:%02x%02x:%02x%02x:%02x%02x/%d lifetime %d expires in %s",
> + prefix->addr.s6_addr[0], prefix->addr.s6_addr[1],
> + prefix->addr.s6_addr[2], prefix->addr.s6_addr[3],
> + prefix->addr.s6_addr[4], prefix->addr.s6_addr[5],
> + prefix->addr.s6_addr[6], prefix->addr.s6_addr[7],
> + prefix->len, lifetime,
Maybe add a macro for this like SD_ID128_FORMAT_STR and SD_ID128_FORMAT_VAL?
> + format_timespan(time_string, FORMAT_TIMESPAN_MAX,
> + lifetime * USEC_PER_SEC, 0));
> +
> + LIST_PREPEND(prefixes, nd->link->prefixes, prefix);
> +
> + } else {
> + if (prefix->len != prefix_opt->nd_opt_pi_prefix_len) {
> + uint8_t prefixlen;
> +
> + prefixlen = (prefix->len < prefix_opt->nd_opt_pi_prefix_len)?
> + prefix->len: prefix_opt->nd_opt_pi_prefix_len;
MIN...
> + log_icmp6_nd(nd, "Prefix length mismatch %d/%d using %d",
> + prefix->len, prefix_opt->nd_opt_pi_prefix_len,
> + prefixlen);
> +
> + prefix->len = prefixlen;
> + }
> +
> + log_icmp6_nd(nd, "Update prefix %02x%02x:%02x%02x:%02x%02x:%02x%02x/%d lifetime %d expires in %s",
> + prefix->addr.s6_addr[0], prefix->addr.s6_addr[1],
> + prefix->addr.s6_addr[2], prefix->addr.s6_addr[3],
> + prefix->addr.s6_addr[4], prefix->addr.s6_addr[5],
> + prefix->addr.s6_addr[6], prefix->addr.s6_addr[7],
> + prefix->len, lifetime,
> + format_timespan(time_string, FORMAT_TIMESPAN_MAX,
> + lifetime * USEC_PER_SEC, 0));
> + }
> +
> + r = icmp6_ra_prefix_set_timeout(nd, prefix, lifetime * USEC_PER_SEC);
> +
> + return r;
> +}
> +
> static int icmp6_ra_parse(sd_icmp6_nd *nd, struct nd_router_advert *ra,
> ssize_t len) {
> void *opt;
> struct nd_opt_hdr *opt_hdr;
> struct nd_opt_mtu *opt_mtu;
> + struct nd_opt_prefix_info *opt_prefix;
> uint32_t mtu;
>
> assert_return(nd, -EINVAL);
> @@ -324,6 +540,12 @@ static int icmp6_ra_parse(sd_icmp6_nd *nd, struct nd_router_advert *ra,
>
> break;
>
> + case ND_OPT_PREFIX_INFORMATION:
> + opt_prefix = opt;
> +
> + icmp6_ra_prefix_update(nd, len, opt_prefix);
> +
> + break;
> }
>
> len -= opt_hdr->nd_opt_len * ICMP6_OPT_LEN_UNITS;
> diff --git a/src/systemd/sd-icmp6-nd.h b/src/systemd/sd-icmp6-nd.h
> index 73ebccf..9139c06 100644
> --- a/src/systemd/sd-icmp6-nd.h
> +++ b/src/systemd/sd-icmp6-nd.h
> @@ -31,6 +31,7 @@ enum {
> ICMP6_EVENT_ROUTER_ADVERTISMENT_TIMEOUT = 1,
> ICMP6_EVENT_ROUTER_ADVERTISMENT_OTHER = 2,
> ICMP6_EVENT_ROUTER_ADVERTISMENT_MANAGED = 3,
Indent the others too?
> + ICMP6_EVENT_ROUTER_ADVERTISMENT_PREFIX_EXPIRED = 4,
> };
>
> typedef struct sd_icmp6_nd sd_icmp6_nd;
> @@ -51,7 +52,12 @@ sd_icmp6_nd *sd_icmp6_nd_ref(sd_icmp6_nd *nd);
> sd_icmp6_nd *sd_icmp6_nd_unref(sd_icmp6_nd *nd);
> int sd_icmp6_nd_new(sd_icmp6_nd **ret);
>
> +int sd_icmp6_prefix_match(struct in6_addr *prefix, uint8_t prefixlen,
> + struct in6_addr *addr);
> +
> int sd_icmp6_ra_get_mtu(sd_icmp6_nd *nd, uint32_t *mtu);
> +int sd_icmp6_ra_get_prefixlen(sd_icmp6_nd *nd, const struct in6_addr *addr,
> + uint8_t *prefixlen);
>
> int sd_icmp6_nd_stop(sd_icmp6_nd *nd);
> int sd_icmp6_router_solicitation_start(sd_icmp6_nd *nd);
Zbyszek
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