--- /dev/null
+From a0358e5ddbc1ef3dec791f11f95f5dbe56087a5e Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Sat, 7 Jun 2014 13:38:48 +0100
+Subject: [PATCH] Handle async notification of address changes using the event
+ system.
+
+---
+ CHANGELOG | 4 ++++
+ src/bpf.c | 6 +++---
+ src/dhcp6.c | 10 ----------
+ src/dnsmasq.c | 13 +++++++++++--
+ src/dnsmasq.h | 6 ++++--
+ src/netlink.c | 39 ++++++++++-----------------------------
+ src/network.c | 11 +++--------
+ 7 files changed, 35 insertions(+), 54 deletions(-)
+
+--- a/CHANGELOG
++++ b/CHANGELOG
+@@ -15,6 +15,10 @@ version 2.71
+ regression introduced in 2.69. Thanks to James Hunt and
+ the Ubuntu crowd for assistance in fixing this.
+
++ Fix race condition which could lock up dnsmasq when an
++ interface goes down and up rapidly. Thanks to Conrad
++ Kostecki for helping to chase this down.
++
+
+ version 2.70
+ Fix crash, introduced in 2.69, on TCP request when dnsmasq
+--- a/src/bpf.c
++++ b/src/bpf.c
+@@ -376,7 +376,7 @@ void route_init(void)
+ die(_("cannot create PF_ROUTE socket: %s"), NULL, EC_BADNET);
+ }
+
+-void route_sock(time_t now)
++void route_sock(void)
+ {
+ struct if_msghdr *msg;
+ int rc = recv(daemon->routefd, daemon->packet, daemon->packet_buff_sz, 0);
+@@ -401,7 +401,7 @@ void route_sock(time_t now)
+ else if (msg->ifm_type == RTM_NEWADDR)
+ {
+ del_family = 0;
+- newaddress(now);
++ send_newaddr();
+ }
+ else if (msg->ifm_type == RTM_DELADDR)
+ {
+@@ -439,7 +439,7 @@ void route_sock(time_t now)
+ of += sizeof(long) - (diff & (sizeof(long) - 1));
+ }
+
+- newaddress(now);
++ send_newaddr();
+ }
+ }
+
+--- a/src/dnsmasq.c
++++ b/src/dnsmasq.c
+@@ -917,10 +917,10 @@ int main (int argc, char **argv)
+
+ #if defined(HAVE_LINUX_NETWORK)
+ if (FD_ISSET(daemon->netlinkfd, &rset))
+- netlink_multicast(now);
++ netlink_multicast();
+ #elif defined(HAVE_BSD_NETWORK)
+ if (FD_ISSET(daemon->routefd, &rset))
+- route_sock(now);
++ route_sock();
+ #endif
+
+ /* Check for changes to resolv files once per second max. */
+@@ -1037,6 +1037,11 @@ void send_alarm(time_t event, time_t now
+ }
+ }
+
++void send_newaddr(void)
++{
++ send_event(pipewrite, EVENT_NEWADDR, 0, NULL);
++}
++
+ void send_event(int fd, int event, int data, char *msg)
+ {
+ struct event_desc ev;
+@@ -1230,6 +1235,10 @@ static void async_event(int pipe, time_t
+ if (daemon->log_file != NULL)
+ log_reopen(daemon->log_file);
+ break;
++
++ case EVENT_NEWADDR:
++ newaddress(now);
++ break;
+
+ case EVENT_TERM:
+ /* Knock all our children on the head. */
+--- a/src/dnsmasq.h
++++ b/src/dnsmasq.h
+@@ -165,6 +165,7 @@ struct event_desc {
+ #define EVENT_LUA_ERR 19
+ #define EVENT_TFTP_ERR 20
+ #define EVENT_INIT 21
++#define EVENT_NEWADDR 22
+
+ /* Exit codes. */
+ #define EC_GOOD 0
+@@ -1289,6 +1290,7 @@ unsigned char *extended_hwaddr(int hwtyp
+ int make_icmp_sock(void);
+ int icmp_ping(struct in_addr addr);
+ #endif
++void send_newaddr(void);
+ void send_alarm(time_t event, time_t now);
+ void send_event(int fd, int event, int data, char *msg);
+ void clear_cache_and_reload(time_t now);
+@@ -1297,7 +1299,7 @@ void poll_resolv(int force, int do_reloa
+ /* netlink.c */
+ #ifdef HAVE_LINUX_NETWORK
+ void netlink_init(void);
+-void netlink_multicast(time_t now);
++void netlink_multicast(void);
+ #endif
+
+ /* bpf.c */
+@@ -1306,7 +1308,7 @@ void init_bpf(void);
+ void send_via_bpf(struct dhcp_packet *mess, size_t len,
+ struct in_addr iface_addr, struct ifreq *ifr);
+ void route_init(void);
+-void route_sock(time_t now);
++void route_sock(void);
+ #endif
+
+ /* bpf.c or netlink.c */
+--- a/src/netlink.c
++++ b/src/netlink.c
+@@ -38,7 +38,7 @@
+ static struct iovec iov;
+ static u32 netlink_pid;
+
+-static int nl_async(struct nlmsghdr *h);
++static void nl_async(struct nlmsghdr *h);
+
+ void netlink_init(void)
+ {
+@@ -142,7 +142,7 @@ int iface_enumerate(int family, void *pa
+ struct nlmsghdr *h;
+ ssize_t len;
+ static unsigned int seq = 0;
+- int callback_ok = 1, newaddr = 0;
++ int callback_ok = 1;
+
+ struct {
+ struct nlmsghdr nlh;
+@@ -191,21 +191,10 @@ int iface_enumerate(int family, void *pa
+ 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;
+- enumerate_interfaces(1); /* reset */
+- }
++ nl_async(h);
+ }
+ else if (h->nlmsg_type == NLMSG_DONE)
+- {
+- /* handle async new interface address arrivals, these have to be done
+- after we complete as we're not re-entrant */
+- if (newaddr)
+- newaddress(dnsmasq_time());
+-
+- return callback_ok;
+- }
++ return callback_ok;
+ else if (h->nlmsg_type == RTM_NEWADDR && family != AF_UNSPEC && family != AF_LOCAL)
+ {
+ struct ifaddrmsg *ifa = NLMSG_DATA(h);
+@@ -330,11 +319,11 @@ int iface_enumerate(int family, void *pa
+ }
+ }
+
+-void netlink_multicast(time_t now)
++void netlink_multicast(void)
+ {
+ ssize_t len;
+ struct nlmsghdr *h;
+- int flags, newaddr = 0;
++ int flags;
+
+ /* don't risk blocking reading netlink messages here. */
+ if ((flags = fcntl(daemon->netlinkfd, F_GETFL)) == -1 ||
+@@ -343,24 +332,19 @@ void netlink_multicast(time_t now)
+
+ if ((len = netlink_recv()) != -1)
+ for (h = (struct nlmsghdr *)iov.iov_base; NLMSG_OK(h, (size_t)len); h = NLMSG_NEXT(h, len))
+- if (nl_async(h))
+- newaddr = 1;
++ nl_async(h);
+
+ /* restore non-blocking status */
+ fcntl(daemon->netlinkfd, F_SETFL, flags);
+-
+- if (newaddr)
+- newaddress(now);
+ }
+
+-static int nl_async(struct nlmsghdr *h)
++static void nl_async(struct nlmsghdr *h)
+ {
+ if (h->nlmsg_type == NLMSG_ERROR)
+ {
+ struct nlmsgerr *err = NLMSG_DATA(h);
+ if (err->error != 0)
+ my_syslog(LOG_ERR, _("netlink returns error: %s"), strerror(-(err->error)));
+- return 0;
+ }
+ else if (h->nlmsg_pid == 0 && h->nlmsg_type == RTM_NEWROUTE)
+ {
+@@ -385,18 +369,15 @@ static int nl_async(struct nlmsghdr *h)
+ else if (daemon->rfd_save && daemon->rfd_save->refcount != 0)
+ fd = daemon->rfd_save->fd;
+ else
+- return 0;
++ return;
+
+ while(sendto(fd, daemon->packet, daemon->packet_len, 0,
+ &daemon->srv_save->addr.sa, sa_len(&daemon->srv_save->addr)) == -1 && retry_send());
+ }
+ }
+- return 0;
+ }
+ else if (h->nlmsg_type == RTM_NEWADDR || h->nlmsg_type == RTM_DELADDR)
+- return 1; /* clever bind mode - rescan */
+-
+- return 0;
++ send_newaddr();
+ }
+ #endif
+
+--- a/src/network.c
++++ b/src/network.c
+@@ -551,7 +551,7 @@ static int iface_allowed_v4(struct in_ad
+ int enumerate_interfaces(int reset)
+ {
+ static struct addrlist *spare = NULL;
+- static int done = 0, active = 0;
++ static int done = 0;
+ struct iface_param param;
+ int errsave, ret = 1;
+ struct addrlist *addr, *tmp;
+@@ -570,14 +570,11 @@ int enumerate_interfaces(int reset)
+ return 1;
+ }
+
+- if (done || active)
++ if (done)
+ return 1;
+
+ done = 1;
+
+- /* protect against recusive calls from iface_enumerate(); */
+- active = 1;
+-
+ if ((param.fd = socket(PF_INET, SOCK_DGRAM, 0)) == -1)
+ return 0;
+
+@@ -677,10 +674,8 @@ int enumerate_interfaces(int reset)
+ }
+
+ errno = errsave;
+-
+ spare = param.spare;
+- active = 0;
+-
++
+ return ret;
+ }
+
projects / openwrt / openwrt.git / commitdiff