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/*
* BIRD -- RAdv Packet Processing
*
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#include <stdlib.h>
#include "radv.h"
struct radv_ra_packet
{
u8 type;
u8 code;
u16 checksum;
u8 current_hop_limit;
u8 flags;
u16 router_lifetime;
u32 reachable_time;
u32 retrans_timer;
};
#define OPT_RA_MANAGED 0x80
#define OPT_RA_OTHER_CFG 0x40
#define OPT_PREFIX 3
#define OPT_MTU 5
struct radv_opt_prefix
{
u8 type;
u8 length;
u8 pxlen;
u8 flags;
u32 valid_lifetime;
u32 preferred_lifetime;
u32 reserved;
ip_addr prefix;
};
#define OPT_PX_ONLINK 0x80
#define OPT_PX_AUTONOMOUS 0x40
struct radv_opt_mtu
{
u8 type;
u8 length;
u16 reserved;
u32 mtu;
};
static struct radv_prefix_config default_prefix = {
.onlink = 1,
.autonomous = 1,
.valid_lifetime = DEFAULT_VALID_LIFETIME,
.preferred_lifetime = DEFAULT_PREFERRED_LIFETIME
};
static struct radv_prefix_config *
radv_prefix_match(struct radv_iface *ifa, struct ifa *a)
{
struct proto *p = &ifa->ra->p;
struct radv_config *cf = (struct radv_config *) (p->cf);
struct radv_prefix_config *pc;
if (a->scope <= SCOPE_LINK)
return NULL;
WALK_LIST(pc, ifa->cf->pref_list)
if ((a->pxlen >= pc->pxlen) && ipa_in_net(a->prefix, pc->prefix, pc->pxlen))
return pc;
WALK_LIST(pc, cf->pref_list)
if ((a->pxlen >= pc->pxlen) && ipa_in_net(a->prefix, pc->prefix, pc->pxlen))
return pc;
return &default_prefix;
}
static void
radv_prepare_ra(struct radv_iface *ifa)
{
struct proto_radv *ra = ifa->ra;
char *buf = ifa->sk->tbuf;
char *bufstart = buf;
char *bufend = buf + ifa->sk->tbsize;
struct radv_ra_packet *pkt = (void *) buf;
pkt->type = ICMPV6_RA;
pkt->code = 0;
pkt->checksum = 0;
pkt->current_hop_limit = ifa->cf->current_hop_limit;
pkt->flags = (ifa->cf->managed ? OPT_RA_MANAGED : 0) |
(ifa->cf->other_config ? OPT_RA_OTHER_CFG : 0);
pkt->router_lifetime = htons(ifa->cf->default_lifetime);
pkt->reachable_time = htonl(ifa->cf->reachable_time);
pkt->retrans_timer = htonl(ifa->cf->retrans_timer);
buf += sizeof(*pkt);
if (ifa->cf->link_mtu)
{
struct radv_opt_mtu *om = (void *) buf;
om->type = OPT_MTU;
om->length = 1;
om->reserved = 0;
om->mtu = htonl(ifa->cf->link_mtu);
buf += sizeof (*om);
}
struct ifa *addr;
WALK_LIST(addr, ifa->iface->addrs)
{
struct radv_prefix_config *pc;
pc = radv_prefix_match(ifa, addr);
if (!pc || pc->skip)
continue;
if (buf + sizeof(struct radv_opt_prefix) > bufend)
{
log(L_WARN "%s: Too many prefixes on interface %s", ra->p.name, ifa->iface->name);
break;
}
struct radv_opt_prefix *op = (void *) buf;
op->type = OPT_PREFIX;
op->length = 4;
op->pxlen = addr->pxlen;
op->flags = (pc->onlink ? OPT_PX_ONLINK : 0) |
(pc->autonomous ? OPT_PX_AUTONOMOUS : 0);
op->valid_lifetime = htonl(pc->valid_lifetime);
op->preferred_lifetime = htonl(pc->preferred_lifetime);
op->reserved = 0;
op->prefix = addr->prefix;
ipa_hton(op->prefix);
buf += sizeof(*op);
}
ifa->plen = buf - bufstart;
}
void
radv_send_ra(struct radv_iface *ifa, int shutdown)
{
struct proto_radv *ra = ifa->ra;
/* We store prepared RA in tbuf */
if (!ifa->plen)
radv_prepare_ra(ifa);
if (shutdown)
{
/* Modify router lifetime to 0, it is not restored because
we suppose that the iface will be removed */
struct radv_ra_packet *pkt = (void *) ifa->sk->tbuf;
pkt->router_lifetime = 0;
}
RADV_TRACE(D_PACKETS, "Sending RA via %s", ifa->iface->name);
sk_send_to(ifa->sk, ifa->plen, AllNodes, 0);
}
static int
radv_rx_hook(sock *sk, int size)
{
struct radv_iface *ifa = sk->data;
struct proto_radv *ra = ifa->ra;
/* We want just packets from sk->iface */
if (sk->lifindex != sk->iface->index)
return 1;
if (ipa_equal(sk->faddr, ifa->addr->ip))
return 1;
if (size < 8)
return 1;
byte *buf = sk->rbuf;
if (buf[1] != 0)
return 1;
/* Validation is a bit sloppy - Hop Limit is not checked and
length of options is ignored for RS and left to later for RA */
switch (buf[0])
{
case ICMPV6_RS:
RADV_TRACE(D_PACKETS, "Received RS from %I via %s",
sk->faddr, ifa->iface->name);
radv_iface_notify(ifa, RA_EV_RS);
return 1;
case ICMPV6_RA:
RADV_TRACE(D_PACKETS, "Received RA from %I via %s",
sk->faddr, ifa->iface->name);
/* FIXME - there should be some checking of received RAs, but we just ignore them */
return 1;
default:
return 1;
}
}
static void
radv_tx_hook(sock *sk)
{
struct radv_iface *ifa = sk->data;
log(L_WARN "%s: TX hook called", ifa->ra->p.name);
}
static void
radv_err_hook(sock *sk, int err)
{
struct radv_iface *ifa = sk->data;
log(L_ERR "%s: Socket error: %m", ifa->ra->p.name, err);
}
int
radv_sk_open(struct radv_iface *ifa)
{
sock *sk = sk_new(ifa->ra->p.pool);
sk->type = SK_IP;
sk->dport = ICMPV6_PROTO;
sk->saddr = IPA_NONE;
sk->ttl = 255; /* Mandatory for Neighbor Discovery packets */
sk->rx_hook = radv_rx_hook;
sk->tx_hook = radv_tx_hook;
sk->err_hook = radv_err_hook;
sk->iface = ifa->iface;
sk->rbsize = 1024; // bufsize(ifa);
sk->tbsize = 1024; // bufsize(ifa);
sk->data = ifa;
sk->flags = SKF_LADDR_RX;
if (sk_open(sk) != 0)
goto err;
sk->saddr = ifa->addr->ip;
/* We want listen just to ICMPv6 messages of type RS and RA */
if (sk_set_icmp_filter(sk, ICMPV6_RS, ICMPV6_RA) < 0)
goto err;
if (sk_setup_multicast(sk) < 0)
goto err;
if (sk_join_group(sk, AllRouters) < 0)
goto err;
ifa->sk = sk;
return 1;
err:
rfree(sk);
return 0;
}
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