mirror of
https://github.com/pi-hole/dnsmasq.git
synced 2025-12-19 10:18:25 +00:00
Improve the performance of DHCP relay.
On machines with many interfaces, enumerating them via netlink on each packet reciept is slow, and unneccesary. All we need is the local address->interface mapping, which can be cached in the relay structures.
This commit is contained in:
Simon Kelley
183
src/dhcp.c
183
src/dhcp.c
@@ -20,8 +20,6 @@
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struct iface_param {
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struct dhcp_context *current;
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struct dhcp_relay *relay;
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struct in_addr relay_local;
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int ind;
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};
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@@ -34,7 +32,7 @@ static int complete_context(struct in_addr local, int if_index, char *label,
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struct in_addr netmask, struct in_addr broadcast, void *vparam);
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static int check_listen_addrs(struct in_addr local, int if_index, char *label,
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struct in_addr netmask, struct in_addr broadcast, void *vparam);
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static int relay_upstream4(struct dhcp_relay *relay, struct dhcp_packet *mess, size_t sz, int iface_index);
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static int relay_upstream4(int iface_index, struct dhcp_packet *mess, size_t sz);
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static struct dhcp_relay *relay_reply4(struct dhcp_packet *mess, char *arrival_interface);
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static int make_fd(int port)
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@@ -307,12 +305,7 @@ void dhcp_packet(time_t now, int pxe_fd)
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for (context = daemon->dhcp; context; context = context->next)
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context->current = context;
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for (relay = daemon->relay4; relay; relay = relay->next)
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relay->current = relay;
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parm.current = NULL;
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parm.relay = NULL;
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parm.relay_local.s_addr = 0;
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parm.ind = iface_index;
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if (!iface_check(AF_INET, (union all_addr *)&iface_addr, ifr.ifr_name, NULL))
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@@ -334,15 +327,19 @@ void dhcp_packet(time_t now, int pxe_fd)
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there is more than one address on the interface in the same subnet */
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complete_context(match.addr, iface_index, NULL, match.netmask, match.broadcast, &parm);
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}
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if (relay_upstream4(iface_index, mess, (size_t)sz))
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return;
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if (!iface_enumerate(AF_INET, &parm, complete_context))
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return;
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/* We're relaying this request */
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if (parm.relay_local.s_addr != 0 &&
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relay_upstream4(parm.relay, mess, (size_t)sz, iface_index))
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/* Check for a relay again after iface_enumerate/complete_context has had
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chance to fill in relay->iface_index fields. This handles first time through
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and any changes in interface config. */
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if (relay_upstream4(iface_index, mess, (size_t)sz))
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return;
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/* May have configured relay, but not DHCP server */
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if (!daemon->dhcp)
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return;
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@@ -631,14 +628,9 @@ static int complete_context(struct in_addr local, int if_index, char *label,
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}
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for (relay = daemon->relay4; relay; relay = relay->next)
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if (if_index == param->ind && relay->local.addr4.s_addr == local.s_addr && relay->current == relay &&
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(param->relay_local.s_addr == 0 || param->relay_local.s_addr == local.s_addr))
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{
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relay->current = param->relay;
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param->relay = relay;
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param->relay_local = local;
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}
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if (relay->local.addr4.s_addr == local.s_addr)
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relay->iface_index = if_index;
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return 1;
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}
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@@ -1079,85 +1071,96 @@ char *host_from_dns(struct in_addr addr)
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return NULL;
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}
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static int relay_upstream4(struct dhcp_relay *relay, struct dhcp_packet *mess, size_t sz, int iface_index)
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static int relay_upstream4(int iface_index, struct dhcp_packet *mess, size_t sz)
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{
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/* ->local is same value for all relays on ->current chain */
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union all_addr from;
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struct in_addr giaddr = mess->giaddr;
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u8 hops = mess->hops;
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struct dhcp_relay *relay;
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if (mess->op != BOOTREQUEST)
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return 0;
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/* source address == relay address */
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from.addr4 = relay->local.addr4;
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for (relay = daemon->relay4; relay; relay = relay->next)
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if (relay->iface_index != 0 && relay->iface_index == iface_index)
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break;
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/* No relay config. */
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if (!relay)
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return 0;
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/* already gatewayed ? */
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if (mess->giaddr.s_addr)
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{
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/* if so check if by us, to stomp on loops. */
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if (mess->giaddr.s_addr == relay->local.addr4.s_addr)
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return 1;
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}
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else
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{
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/* plug in our address */
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mess->giaddr.s_addr = relay->local.addr4.s_addr;
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}
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if ((mess->hops++) > 20)
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return 1;
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for (; relay; relay = relay->current)
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{
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union mysockaddr to;
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to.sa.sa_family = AF_INET;
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to.in.sin_addr = relay->server.addr4;
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to.in.sin_port = htons(daemon->dhcp_server_port);
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/* Broadcasting to server. */
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if (relay->server.addr4.s_addr == 0)
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{
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struct ifreq ifr;
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if (relay->interface)
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safe_strncpy(ifr.ifr_name, relay->interface, IF_NAMESIZE);
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if (!relay->interface || strchr(relay->interface, '*') ||
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ioctl(daemon->dhcpfd, SIOCGIFBRDADDR, &ifr) == -1)
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{
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my_syslog(MS_DHCP | LOG_ERR, _("Cannot broadcast DHCP relay via interface %s"), relay->interface);
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return 1;
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}
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to.in.sin_addr = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr;
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}
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#ifdef HAVE_DUMPFILE
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for (; relay; relay = relay->next)
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if (relay->iface_index != 0 && relay->iface_index == iface_index)
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{
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union mysockaddr fromsock;
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fromsock.in.sin_port = htons(daemon->dhcp_server_port);
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fromsock.in.sin_addr = from.addr4;
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fromsock.sa.sa_family = AF_INET;
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union mysockaddr to;
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union all_addr from;
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mess->hops = hops;
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mess->giaddr = giaddr;
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dump_packet(DUMP_DHCP, (void *)mess, sz, &fromsock, &to, 0);
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}
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#endif
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send_from(daemon->dhcpfd, 0, (char *)mess, sz, &to, &from, 0);
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if (option_bool(OPT_LOG_OPTS))
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if ((mess->hops++) > 20)
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continue;
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/* source address == relay address */
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from.addr4 = relay->local.addr4;
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/* already gatewayed ? */
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if (giaddr.s_addr)
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{
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/* if so check if by us, to stomp on loops. */
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if (giaddr.s_addr == relay->local.addr4.s_addr)
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continue;
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}
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else
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{
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/* plug in our address */
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mess->giaddr.s_addr = relay->local.addr4.s_addr;
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}
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to.sa.sa_family = AF_INET;
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to.in.sin_addr = relay->server.addr4;
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to.in.sin_port = htons(daemon->dhcp_server_port);
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/* Broadcasting to server. */
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if (relay->server.addr4.s_addr == 0)
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{
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struct ifreq ifr;
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if (relay->interface)
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safe_strncpy(ifr.ifr_name, relay->interface, IF_NAMESIZE);
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if (!relay->interface || strchr(relay->interface, '*') ||
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ioctl(daemon->dhcpfd, SIOCGIFBRDADDR, &ifr) == -1)
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{
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my_syslog(MS_DHCP | LOG_ERR, _("Cannot broadcast DHCP relay via interface %s"), relay->interface);
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continue;
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}
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to.in.sin_addr = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr;
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}
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#ifdef HAVE_DUMPFILE
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{
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inet_ntop(AF_INET, &relay->local, daemon->addrbuff, ADDRSTRLEN);
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if (relay->server.addr4.s_addr == 0)
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snprintf(daemon->dhcp_buff2, DHCP_BUFF_SZ, _("broadcast via %s"), relay->interface);
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else
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inet_ntop(AF_INET, &relay->server.addr4, daemon->dhcp_buff2, DHCP_BUFF_SZ);
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my_syslog(MS_DHCP | LOG_INFO, _("DHCP relay at %s -> %s"), daemon->addrbuff, daemon->dhcp_buff2);
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union mysockaddr fromsock;
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fromsock.in.sin_port = htons(daemon->dhcp_server_port);
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fromsock.in.sin_addr = from.addr4;
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fromsock.sa.sa_family = AF_INET;
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dump_packet(DUMP_DHCP, (void *)mess, sz, &fromsock, &to, 0);
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}
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/* Save this for replies */
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relay->iface_index = iface_index;
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}
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#endif
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send_from(daemon->dhcpfd, 0, (char *)mess, sz, &to, &from, 0);
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if (option_bool(OPT_LOG_OPTS))
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{
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inet_ntop(AF_INET, &relay->local, daemon->addrbuff, ADDRSTRLEN);
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if (relay->server.addr4.s_addr == 0)
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snprintf(daemon->dhcp_buff2, DHCP_BUFF_SZ, _("broadcast via %s"), relay->interface);
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else
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inet_ntop(AF_INET, &relay->server.addr4, daemon->dhcp_buff2, DHCP_BUFF_SZ);
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my_syslog(MS_DHCP | LOG_INFO, _("DHCP relay at %s -> %s"), daemon->addrbuff, daemon->dhcp_buff2);
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}
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}
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return 1;
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}
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