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Add --bind-dynamic

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This commit is contained in:
Simon Kelley
2012-06-20 11:23:38 +01:00
parent 4ce4f3779b
commit 54dd393f39
8 changed files with 131 additions and 77 deletions
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149
src/netlink.c
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@@ -38,7 +38,7 @@
static struct iovec iov;
static u32 netlink_pid;
static void nl_err(struct nlmsghdr *h);
static int nl_async(struct nlmsghdr *h);
static void nl_routechange(struct nlmsghdr *h);
void netlink_init(void)
@@ -49,10 +49,13 @@ void netlink_init(void)
addr.nl_family = AF_NETLINK;
addr.nl_pad = 0;
addr.nl_pid = 0; /* autobind */
#ifdef HAVE_IPV6
addr.nl_groups = RTMGRP_IPV4_ROUTE | RTMGRP_IPV6_ROUTE;
#else
addr.nl_groups = RTMGRP_IPV4_ROUTE;
if (option_bool(OPT_CLEVERBIND))
addr.nl_groups |= RTMGRP_IPV4_IFADDR;
#ifdef HAVE_IPV6
addr.nl_groups |= RTMGRP_IPV6_ROUTE;
if (daemon->ra_contexts || option_bool(OPT_CLEVERBIND))
addr.nl_groups |= RTMGRP_IPV6_IFADDR;
#endif
/* May not be able to have permission to set multicast groups don't die in that case */
@@ -136,7 +139,7 @@ int iface_enumerate(int family, void *parm, int (*callback)())
struct nlmsghdr *h;
ssize_t len;
static unsigned int seq = 0;
int callback_ok = 1;
int callback_ok = 1, newaddr = 0;
struct {
struct nlmsghdr nlh;
@@ -182,12 +185,24 @@ int iface_enumerate(int family, void *parm, int (*callback)())
}
for (h = (struct nlmsghdr *)iov.iov_base; NLMSG_OK(h, (size_t)len); h = NLMSG_NEXT(h, len))
if (h->nlmsg_seq != seq || h->nlmsg_pid != netlink_pid)
nl_routechange(h); /* May be multicast arriving async */
else if (h->nlmsg_type == NLMSG_ERROR)
nl_err(h);
if (h->nlmsg_seq != seq || h->nlmsg_pid != netlink_pid || h->nlmsg_type == NLMSG_ERROR)
{
/* May be multicast arriving async */
if (nl_async(h))
newaddr = 1;
}
else if (h->nlmsg_type == NLMSG_DONE)
return callback_ok;
{
/* handle async new interface address arrivals, these have to be done
after we complete as we're not re-entrant */
if (newaddr)
{
enumerate_interfaces();
create_bound_listeners(0);
}
return callback_ok;
}
else if (h->nlmsg_type == RTM_NEWADDR && family != AF_UNSPEC && family != AF_LOCAL)
{
struct ifaddrmsg *ifa = NLMSG_DATA(h);
@@ -295,7 +310,7 @@ void netlink_multicast(void)
{
ssize_t len;
struct nlmsghdr *h;
int flags;
int flags, newaddr = 0;
/* don't risk blocking reading netlink messages here. */
if ((flags = fcntl(daemon->netlinkfd, F_GETFL)) == -1 ||
@@ -303,71 +318,83 @@ void netlink_multicast(void)
return;
if ((len = netlink_recv()) != -1)
{
for (h = (struct nlmsghdr *)iov.iov_base; NLMSG_OK(h, (size_t)len); h = NLMSG_NEXT(h, len))
if (h->nlmsg_type == NLMSG_ERROR)
nl_err(h);
else
nl_routechange(h);
}
/* restore non-blocking status */
fcntl(daemon->netlinkfd, F_SETFL, flags);
}
static void nl_err(struct nlmsghdr *h)
{
struct nlmsgerr *err = NLMSG_DATA(h);
for (h = (struct nlmsghdr *)iov.iov_base; NLMSG_OK(h, (size_t)len); h = NLMSG_NEXT(h, len))
if (nl_async(h))
newaddr = 1;
if (err->error != 0)
my_syslog(LOG_ERR, _("netlink returns error: %s"), strerror(-(err->error)));
/* restore non-blocking status */
fcntl(daemon->netlinkfd, F_SETFL, flags);
if (newaddr)
{
enumerate_interfaces();
create_bound_listeners(0);
}
}
static int nl_async(struct nlmsghdr *h)
{
if (h->nlmsg_type == NLMSG_ERROR)
{
struct nlmsgerr *err = NLMSG_DATA(h);
my_syslog(LOG_ERR, _("netlink returns error: %s"), strerror(-(err->error)));
return 0;
}
else if (h->nlmsg_pid == 0 && h->nlmsg_type == RTM_NEWROUTE)
{
nl_routechange(h);
return 0;
}
else if (h->nlmsg_type == RTM_NEWADDR)
{
#ifdef HAVE_DHCP6
/* force RAs to sync new network and pick up new interfaces. */
if (daemon->ra_contexts)
{
schedule_subnet_map();
ra_start_unsolicted(dnsmasq_time(), NULL);
/* cause lease_update_file to run after we return, in case we were called from
iface_enumerate and can't re-enter it now */
send_alarm(0, 0);
}
return !!option_bool(OPT_CLEVERBIND); /* clever bind mode - rescan */
}
#endif
return 0;
}
/* We arrange to receive netlink multicast messages whenever the network route is added.
If this happens and we still have a DNS packet in the buffer, we re-send it.
This helps on DoD links, where frequently the packet which triggers dialling is
a DNS query, which then gets lost. By re-sending, we can avoid the lookup
failing. Note that we only accept these messages from the kernel (pid == 0) */
failing. */
static void nl_routechange(struct nlmsghdr *h)
{
if (h->nlmsg_pid == 0 && h->nlmsg_type == RTM_NEWROUTE)
struct rtmsg *rtm = NLMSG_DATA(h);
int fd;
if (rtm->rtm_type != RTN_UNICAST || rtm->rtm_scope != RT_SCOPE_LINK)
return;
/* Force re-reading resolv file right now, for luck. */
daemon->last_resolv = 0;
if (daemon->srv_save)
{
struct rtmsg *rtm = NLMSG_DATA(h);
int fd;
if (rtm->rtm_type != RTN_UNICAST || rtm->rtm_scope != RT_SCOPE_LINK)
if (daemon->srv_save->sfd)
fd = daemon->srv_save->sfd->fd;
else if (daemon->rfd_save && daemon->rfd_save->refcount != 0)
fd = daemon->rfd_save->fd;
else
return;
/* Force re-reading resolv file right now, for luck. */
daemon->last_resolv = 0;
#ifdef HAVE_DHCP6
/* force RAs to sync new network and pick up new interfaces. */
if (daemon->ra_contexts)
{
schedule_subnet_map();
ra_start_unsolicted(dnsmasq_time(), NULL);
/* cause lease_update_file to run after we return, in case we were called from
iface_enumerate and can't re-enter it now */
send_alarm(0, 0);
}
#endif
if (daemon->srv_save)
{
if (daemon->srv_save->sfd)
fd = daemon->srv_save->sfd->fd;
else if (daemon->rfd_save && daemon->rfd_save->refcount != 0)
fd = daemon->rfd_save->fd;
else
return;
while(sendto(fd, daemon->packet, daemon->packet_len, 0,
&daemon->srv_save->addr.sa, sa_len(&daemon->srv_save->addr)) == -1 && retry_send());
}
while(sendto(fd, daemon->packet, daemon->packet_len, 0,
&daemon->srv_save->addr.sa, sa_len(&daemon->srv_save->addr)) == -1 && retry_send());
}
}
#endif