Pi-Hole/dnsmasq
1
0
Fork 0
mirror of https://github.com/pi-hole/dnsmasq.git synced 2025-12-19 10:18:25 +00:00
Code Issues Packages Projects Releases Wiki Activity

Add --dhcp-relay config option.

Browse Source
This commit is contained in:
Simon Kelley
2013-09-04 18:01:38 +01:00
parent 6692a1a53f
commit ff7eea27e7
12 changed files with 548 additions and 196 deletions
Download Patch File Download Diff File Expand all files Collapse all files

208
src/dhcp.c
View File

@@ -20,6 +20,8 @@
struct iface_param {
struct dhcp_context *current;
struct dhcp_relay *relay;
struct in_addr relay_local;
int ind;
};
@@ -32,6 +34,8 @@ static int complete_context(struct in_addr local, int if_index, char *label,
struct in_addr netmask, struct in_addr broadcast, void *vparam);
static int check_listen_addrs(struct in_addr local, int if_index, char *label,
struct in_addr netmask, struct in_addr broadcast, void *vparam);
static int relay_upstream4(struct dhcp_relay *relay, struct dhcp_packet *mess, size_t sz, int iface_index);
static struct dhcp_relay *relay_reply4(struct dhcp_packet *mess, char *arrival_interface);
static int make_fd(int port)
{
@@ -132,6 +136,8 @@ void dhcp_packet(time_t now, int pxe_fd)
int fd = pxe_fd ? daemon->pxefd : daemon->dhcpfd;
struct dhcp_packet *mess;
struct dhcp_context *context;
struct dhcp_relay *relay;
int is_relay_reply = 0;
struct iname *tmp;
struct ifreq ifr;
struct msghdr msg;
@@ -250,57 +256,86 @@ void dhcp_packet(time_t now, int pxe_fd)
unicast_dest = 1;
#endif
ifr.ifr_addr.sa_family = AF_INET;
if (ioctl(daemon->dhcpfd, SIOCGIFADDR, &ifr) != -1 )
iface_addr = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr;
if ((relay = relay_reply4((struct dhcp_packet *)daemon->dhcp_packet.iov_base, ifr.ifr_name)))
{
/* Reply from server, using us as relay. */
iface_index = relay->iface_index;
if (!indextoname(daemon->dhcpfd, iface_index, ifr.ifr_name))
return;
is_relay_reply = 1;
iov.iov_len = sz;
#ifdef HAVE_LINUX_NETWORK
strncpy(arp_req.arp_dev, ifr.ifr_name, 16);
#endif
}
else
{
my_syslog(MS_DHCP | LOG_WARNING, _("DHCP packet received on %s which has no address"), ifr.ifr_name);
return;
}
for (tmp = daemon->dhcp_except; tmp; tmp = tmp->next)
if (tmp->name && wildcard_match(tmp->name, ifr.ifr_name))
return;
/* unlinked contexts are marked by context->current == context */
for (context = daemon->dhcp; context; context = context->next)
context->current = context;
parm.current = NULL;
parm.ind = iface_index;
if (!iface_check(AF_INET, (struct all_addr *)&iface_addr, ifr.ifr_name, NULL))
{
/* If we failed to match the primary address of the interface, see if we've got a --listen-address
for a secondary */
struct match_param match;
ifr.ifr_addr.sa_family = AF_INET;
if (ioctl(daemon->dhcpfd, SIOCGIFADDR, &ifr) != -1 )
iface_addr = ((struct sockaddr_in *) &ifr.ifr_addr)->sin_addr;
else
{
my_syslog(MS_DHCP | LOG_WARNING, _("DHCP packet received on %s which has no address"), ifr.ifr_name);
return;
}
match.matched = 0;
match.ind = iface_index;
for (tmp = daemon->dhcp_except; tmp; tmp = tmp->next)
if (tmp->name && wildcard_match(tmp->name, ifr.ifr_name))
return;
if (!daemon->if_addrs ||
!iface_enumerate(AF_INET, &match, check_listen_addrs) ||
!match.matched)
/* unlinked contexts/relays are marked by context->current == context */
for (context = daemon->dhcp; context; context = context->next)
context->current = context;
for (relay = daemon->relay4; relay; relay = relay->next)
relay->current = relay;
parm.current = NULL;
parm.relay = NULL;
parm.relay_local.s_addr = 0;
parm.ind = iface_index;
if (!iface_check(AF_INET, (struct all_addr *)&iface_addr, ifr.ifr_name, NULL))
{
/* If we failed to match the primary address of the interface, see if we've got a --listen-address
for a secondary */
struct match_param match;
match.matched = 0;
match.ind = iface_index;
if (!daemon->if_addrs ||
!iface_enumerate(AF_INET, &match, check_listen_addrs) ||
!match.matched)
return;
iface_addr = match.addr;
/* make sure secondary address gets priority in case
there is more than one address on the interface in the same subnet */
complete_context(match.addr, iface_index, NULL, match.netmask, match.broadcast, &parm);
}
if (!iface_enumerate(AF_INET, &parm, complete_context))
return;
iface_addr = match.addr;
/* make sure secondary address gets priority in case
there is more than one address on the interface in the same subnet */
complete_context(match.addr, iface_index, NULL, match.netmask, match.broadcast, &parm);
}
/* We're relaying this request */
if (parm.relay_local.s_addr != 0 &&
relay_upstream4(parm.relay, (struct dhcp_packet *)daemon->dhcp_packet.iov_base, (size_t)sz, iface_index))
return;
/* May have configured relay, but not DHCP server */
if (!daemon->dhcp)
return;
lease_prune(NULL, now); /* lose any expired leases */
iov.iov_len = dhcp_reply(parm.current, ifr.ifr_name, iface_index, (size_t)sz,
now, unicast_dest, &is_inform, pxe_fd, iface_addr);
lease_update_file(now);
lease_update_dns(0);
if (!iface_enumerate(AF_INET, &parm, complete_context))
return;
lease_prune(NULL, now); /* lose any expired leases */
iov.iov_len = dhcp_reply(parm.current, ifr.ifr_name, iface_index, (size_t)sz,
now, unicast_dest, &is_inform, pxe_fd, iface_addr);
lease_update_file(now);
lease_update_dns(0);
if (iov.iov_len == 0)
return;
if (iov.iov_len == 0)
return;
}
msg.msg_name = &dest;
msg.msg_namelen = sizeof(dest);
@@ -321,7 +356,7 @@ void dhcp_packet(time_t now, int pxe_fd)
if (mess->ciaddr.s_addr != 0)
dest.sin_addr = mess->ciaddr;
}
else if (mess->giaddr.s_addr)
else if (mess->giaddr.s_addr && !is_relay_reply)
{
/* Send to BOOTP relay */
dest.sin_port = htons(daemon->dhcp_server_port);
@@ -334,7 +369,7 @@ void dhcp_packet(time_t now, int pxe_fd)
source port too, and send back to that. If we're replying
to a DHCPINFORM, trust the source address always. */
if ((!is_inform && dest.sin_addr.s_addr != mess->ciaddr.s_addr) ||
dest.sin_port == 0 || dest.sin_addr.s_addr == 0)
dest.sin_port == 0 || dest.sin_addr.s_addr == 0 || is_relay_reply)
{
dest.sin_port = htons(daemon->dhcp_client_port);
dest.sin_addr = mess->ciaddr;
@@ -450,6 +485,7 @@ static int complete_context(struct in_addr local, int if_index, char *label,
struct in_addr netmask, struct in_addr broadcast, void *vparam)
{
struct dhcp_context *context;
struct dhcp_relay *relay;
struct iface_param *param = vparam;
(void)label;
@@ -495,6 +531,15 @@ static int complete_context(struct in_addr local, int if_index, char *label,
}
}
for (relay = daemon->relay4; relay; relay = relay->next)
if (if_index == param->ind && relay->local.addr.addr4.s_addr == local.s_addr && relay->current == relay &&
(param->relay_local.s_addr == 0 || param->relay_local.s_addr == local.s_addr))
{
relay->current = param->relay;
param->relay = relay;
param->relay_local = local;
}
return 1;
}
@@ -988,5 +1033,74 @@ char *host_from_dns(struct in_addr addr)
return NULL;
}
#endif
static int relay_upstream4(struct dhcp_relay *relay, struct dhcp_packet *mess, size_t sz, int iface_index)
{
/* ->local is same value for all relays on ->current chain */
struct all_addr from;
if (mess->op != BOOTREQUEST)
return 0;
/* source address == relay address */
from.addr.addr4 = relay->local.addr.addr4;
/* already gatewayed ? */
if (mess->giaddr.s_addr)
{
/* if so check if by us, to stomp on loops. */
if (mess->giaddr.s_addr == relay->local.addr.addr4.s_addr)
return 1;
}
else
{
/* plug in our address */
mess->giaddr.s_addr = relay->local.addr.addr4.s_addr;
}
if ((mess->hops++) > 20)
return 1;
for (; relay; relay = relay->current)
{
union mysockaddr to;
to.sa.sa_family = AF_INET;
to.in.sin_addr = relay->server.addr.addr4;
to.in.sin_port = htons(daemon->dhcp_server_port);
send_from(daemon->dhcpfd, 0, (char *)mess, sz, &to, &from, 0);
if (option_bool(OPT_LOG_OPTS))
{
inet_ntop(AF_INET, &relay->local, daemon->addrbuff, ADDRSTRLEN);
my_syslog(MS_DHCP | LOG_INFO, _("DHCP relay %s -> %s"), daemon->addrbuff, inet_ntoa(relay->server.addr.addr4));
}
/* Save this for replies */
relay->iface_index = iface_index;
}
return 1;
}
static struct dhcp_relay *relay_reply4(struct dhcp_packet *mess, char *arrival_interface)
{
struct dhcp_relay *relay;
if (mess->giaddr.s_addr == 0 || mess->op != BOOTREPLY)
return NULL;
for (relay = daemon->relay4; relay; relay = relay->next)
{
if (mess->giaddr.s_addr == relay->local.addr.addr4.s_addr)
{
if (!relay->interface || wildcard_match(relay->interface, arrival_interface))
return relay->iface_index != 0 ? relay : NULL;
}
}
return NULL;
}
#endif