mirror of
https://github.com/pi-hole/dnsmasq.git
synced 2025-12-19 18:28:25 +00:00
import of dnsmasq-2.28.tar.gz
This commit is contained in:
Simon Kelley
296
src/netlink.c
296
src/netlink.c
@@ -1,4 +1,4 @@
|
||||
/* dnsmasq is Copyright (c) 2000-2006 Simon Kelley
|
||||
/* dnsmasq is Copyright (c) 2000-2006 Simon Kelley
|
||||
|
||||
This program is free software; you can redistribute it and/or modify
|
||||
it under the terms of the GNU General Public License as published by
|
||||
@@ -12,36 +12,36 @@
|
||||
|
||||
#include "dnsmasq.h"
|
||||
|
||||
#ifdef HAVE_RTNETLINK
|
||||
#ifdef HAVE_LINUX_NETWORK
|
||||
|
||||
#include <linux/types.h>
|
||||
#include <linux/netlink.h>
|
||||
#include <linux/rtnetlink.h>
|
||||
|
||||
static struct iovec iov[1];
|
||||
static struct iovec iov;
|
||||
|
||||
static void nl_err(struct nlmsghdr *h);
|
||||
static void nl_routechange(struct daemon *daemon, struct nlmsghdr *h);
|
||||
|
||||
void netlink_init(struct daemon *daemon)
|
||||
{
|
||||
struct sockaddr_nl addr;
|
||||
daemon->netlinkfd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
|
||||
|
||||
if (daemon->netlinkfd < 0)
|
||||
return; /* no kernel support */
|
||||
|
||||
addr.nl_family = AF_NETLINK;
|
||||
addr.nl_pad = 0;
|
||||
addr.nl_pid = getpid();
|
||||
addr.nl_pid = 0; /* autobind */
|
||||
#ifdef HAVE_IPV6
|
||||
addr.nl_groups = RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_IFADDR | RTMGRP_IPV4_ROUTE | RTMGRP_IPV6_ROUTE;
|
||||
addr.nl_groups = RTMGRP_IPV4_ROUTE | RTMGRP_IPV6_ROUTE;
|
||||
#else
|
||||
addr.nl_groups = RTMGRP_IPV4_IFADDR | RTMGRP_IPV4_ROUTE;
|
||||
addr.nl_groups = RTMGRP_IPV4_ROUTE;
|
||||
#endif
|
||||
|
||||
if (bind(daemon->netlinkfd, (struct sockaddr *)&addr, sizeof(addr)) < 0)
|
||||
die(_("cannot bind netlink socket: %s"), NULL);
|
||||
|
||||
iov[0].iov_len = 200;
|
||||
iov[0].iov_base = safe_malloc(iov[0].iov_len);
|
||||
if ((daemon->netlinkfd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE)) == -1 ||
|
||||
bind(daemon->netlinkfd, (struct sockaddr *)&addr, sizeof(addr)) == -1)
|
||||
die(_("cannot create RTnetlink socket: %s"), NULL);
|
||||
|
||||
iov.iov_len = 200;
|
||||
iov.iov_base = safe_malloc(iov.iov_len);
|
||||
}
|
||||
|
||||
static ssize_t netlink_recv(struct daemon *daemon)
|
||||
@@ -51,162 +51,218 @@ static ssize_t netlink_recv(struct daemon *daemon)
|
||||
|
||||
msg.msg_control = NULL;
|
||||
msg.msg_controllen = 0;
|
||||
msg.msg_flags = 0;
|
||||
msg.msg_name = NULL;
|
||||
msg.msg_namelen = 0;
|
||||
msg.msg_iov = iov;
|
||||
msg.msg_iov = &iov;
|
||||
msg.msg_iovlen = 1;
|
||||
|
||||
retry:
|
||||
while ((rc = recvmsg(daemon->netlinkfd, &msg, MSG_PEEK)) == -1 && retry_send());
|
||||
|
||||
if (rc == -1)
|
||||
return -1;
|
||||
|
||||
if (msg.msg_flags & MSG_TRUNC)
|
||||
while (1)
|
||||
{
|
||||
size_t newsz = iov[0].iov_len + 100;
|
||||
void *new = realloc(iov[0].iov_base, newsz);
|
||||
if (!new)
|
||||
msg.msg_flags = 0;
|
||||
while ((rc = recvmsg(daemon->netlinkfd, &msg, MSG_PEEK)) == -1 && errno == EINTR);
|
||||
|
||||
/* 2.2.x doesn't suport MSG_PEEK at all, returning EOPNOTSUPP, so we just grab a
|
||||
big buffer and pray in that case. */
|
||||
if (rc == -1 && errno == EOPNOTSUPP)
|
||||
{
|
||||
if (!expand_buf(&iov, 2000))
|
||||
return -1;
|
||||
break;
|
||||
}
|
||||
|
||||
if (rc == -1 || !(msg.msg_flags & MSG_TRUNC))
|
||||
break;
|
||||
|
||||
if (!expand_buf(&iov, iov.iov_len + 100))
|
||||
return -1;
|
||||
iov[0].iov_len = newsz;
|
||||
iov[0].iov_base = new;
|
||||
goto retry;
|
||||
}
|
||||
|
||||
while ((rc = recvmsg(daemon->netlinkfd, &msg, 0)) == -1 && retry_send());
|
||||
|
||||
/* finally, read it for real */
|
||||
while ((rc = recvmsg(daemon->netlinkfd, &msg, 0)) == -1 && errno == EINTR);
|
||||
|
||||
return rc;
|
||||
}
|
||||
|
||||
int netlink_process(struct daemon *daemon, int index, struct in_addr relay,
|
||||
struct in_addr primary, struct dhcp_context **retp)
|
||||
int iface_enumerate(struct daemon *daemon, void *parm, int (*ipv4_callback)(), int (*ipv6_callback)())
|
||||
{
|
||||
struct sockaddr_nl addr;
|
||||
struct nlmsghdr *h;
|
||||
int found_primary = 0;
|
||||
ssize_t len;
|
||||
struct dhcp_context *ret = NULL;
|
||||
static unsigned int seq = 0;
|
||||
int family = AF_INET;
|
||||
|
||||
struct {
|
||||
struct nlmsghdr nlh;
|
||||
struct rtgenmsg g;
|
||||
} req;
|
||||
|
||||
if (daemon->netlinkfd == -1)
|
||||
return 0;
|
||||
|
||||
addr.nl_family = AF_NETLINK;
|
||||
addr.nl_pad = 0;
|
||||
addr.nl_groups = 0;
|
||||
addr.nl_pid = 0; /* address to kernel */
|
||||
|
||||
again:
|
||||
req.nlh.nlmsg_len = sizeof(req);
|
||||
req.nlh.nlmsg_type = RTM_GETADDR;
|
||||
req.nlh.nlmsg_flags = NLM_F_ROOT | NLM_F_MATCH | NLM_F_REQUEST;
|
||||
req.nlh.nlmsg_pid = 0;
|
||||
req.nlh.nlmsg_seq = ++seq;
|
||||
req.g.rtgen_family = AF_INET;
|
||||
req.g.rtgen_family = family;
|
||||
|
||||
/* Don't block in recvfrom if send fails */
|
||||
while((len = sendto(daemon->netlinkfd, (void *)&req, sizeof(req), 0,
|
||||
(struct sockaddr *)&addr, sizeof(addr))) == -1 && retry_send());
|
||||
|
||||
if (len == -1)
|
||||
{
|
||||
/* if RTnetlink not configured in the kernel, don't keep trying. */
|
||||
if (errno == ECONNREFUSED)
|
||||
{
|
||||
close(daemon->netlinkfd);
|
||||
daemon->netlinkfd = -1;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
get_next:
|
||||
if ((len = netlink_recv(daemon)) == -1)
|
||||
return 0;
|
||||
|
||||
for (h = (struct nlmsghdr *)iov[0].iov_base; NLMSG_OK(h, (unsigned int)len); h = NLMSG_NEXT(h, len))
|
||||
if (len == -1)
|
||||
return 0;
|
||||
|
||||
while (1)
|
||||
{
|
||||
if (h->nlmsg_seq != seq)
|
||||
goto get_next;
|
||||
|
||||
if (h->nlmsg_type == NLMSG_DONE)
|
||||
break;
|
||||
|
||||
if (h->nlmsg_type == NLMSG_ERROR)
|
||||
if ((len = netlink_recv(daemon)) == -1)
|
||||
return 0;
|
||||
|
||||
if (h->nlmsg_type == RTM_NEWADDR)
|
||||
{
|
||||
struct ifaddrmsg *ifa = NLMSG_DATA(h);
|
||||
if (ifa->ifa_index == index && ifa->ifa_family == AF_INET)
|
||||
{
|
||||
struct rtattr *rta = IFA_RTA(ifa);
|
||||
unsigned int len1 = h->nlmsg_len - NLMSG_LENGTH(sizeof(*ifa));
|
||||
struct in_addr netmask, addr, broadcast;
|
||||
|
||||
netmask.s_addr = htonl(0xffffffff << (32 - ifa->ifa_prefixlen));
|
||||
addr.s_addr = 0;
|
||||
broadcast.s_addr = 0;
|
||||
|
||||
while (RTA_OK(rta, len1))
|
||||
{
|
||||
if (rta->rta_type == IFA_LOCAL)
|
||||
addr = *((struct in_addr *)(rta+1));
|
||||
else if (rta->rta_type == IFA_BROADCAST)
|
||||
broadcast = *((struct in_addr *)(rta+1));
|
||||
|
||||
rta = RTA_NEXT(rta, len1);
|
||||
}
|
||||
|
||||
if (addr.s_addr)
|
||||
{
|
||||
ret = complete_context(daemon, addr, ret, netmask, broadcast, relay, primary);
|
||||
if (addr.s_addr == primary.s_addr)
|
||||
found_primary = 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 if (h->nlmsg_seq != seq)
|
||||
nl_routechange(daemon, h); /* May be multicast arriving async */
|
||||
else if (h->nlmsg_type == NLMSG_DONE)
|
||||
{
|
||||
#ifdef HAVE_IPV6
|
||||
if (family == AF_INET && ipv6_callback)
|
||||
{
|
||||
family = AF_INET6;
|
||||
goto again;
|
||||
}
|
||||
#endif
|
||||
return 1;
|
||||
}
|
||||
else if (h->nlmsg_type == RTM_NEWADDR)
|
||||
{
|
||||
struct ifaddrmsg *ifa = NLMSG_DATA(h);
|
||||
struct rtattr *rta = IFA_RTA(ifa);
|
||||
unsigned int len1 = h->nlmsg_len - NLMSG_LENGTH(sizeof(*ifa));
|
||||
|
||||
if (ifa->ifa_family == AF_INET)
|
||||
{
|
||||
struct in_addr netmask, addr, broadcast;
|
||||
|
||||
netmask.s_addr = htonl(0xffffffff << (32 - ifa->ifa_prefixlen));
|
||||
addr.s_addr = 0;
|
||||
broadcast.s_addr = 0;
|
||||
|
||||
while (RTA_OK(rta, len1))
|
||||
{
|
||||
if (rta->rta_type == IFA_LOCAL)
|
||||
addr = *((struct in_addr *)(rta+1));
|
||||
else if (rta->rta_type == IFA_BROADCAST)
|
||||
broadcast = *((struct in_addr *)(rta+1));
|
||||
|
||||
rta = RTA_NEXT(rta, len1);
|
||||
}
|
||||
|
||||
if (addr.s_addr && ipv4_callback)
|
||||
if (!((*ipv4_callback)(daemon, addr, ifa->ifa_index, netmask, broadcast, parm)))
|
||||
return 0;
|
||||
}
|
||||
#ifdef HAVE_IPV6
|
||||
else if (ifa->ifa_family == AF_INET6)
|
||||
{
|
||||
struct in6_addr *addrp = NULL;
|
||||
while (RTA_OK(rta, len1))
|
||||
{
|
||||
if (rta->rta_type == IFA_ADDRESS)
|
||||
addrp = ((struct in6_addr *)(rta+1));
|
||||
|
||||
rta = RTA_NEXT(rta, len1);
|
||||
}
|
||||
|
||||
if (addrp && ipv6_callback)
|
||||
if (!((*ipv6_callback)(daemon, addrp, ifa->ifa_index, ifa->ifa_index, parm)))
|
||||
return 0;
|
||||
}
|
||||
#endif
|
||||
}
|
||||
}
|
||||
|
||||
*retp = ret;
|
||||
return found_primary;
|
||||
}
|
||||
|
||||
|
||||
/* We arrange to receive netlink multicast messages whenever the network config changes.
|
||||
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. */
|
||||
void netlink_multicast(struct daemon *daemon)
|
||||
{
|
||||
ssize_t len;
|
||||
struct nlmsghdr *h;
|
||||
|
||||
if ((len = netlink_recv(daemon)) == -1)
|
||||
return;
|
||||
|
||||
if (!daemon->srv_save)
|
||||
return;
|
||||
|
||||
for (h = (struct nlmsghdr *)iov[0].iov_base; NLMSG_OK(h, (unsigned int)len); h = NLMSG_NEXT(h, len))
|
||||
if ((len = netlink_recv(daemon)) != -1)
|
||||
{
|
||||
if (h->nlmsg_type == NLMSG_DONE || h->nlmsg_type == NLMSG_ERROR)
|
||||
break;
|
||||
|
||||
if (h->nlmsg_type == RTM_NEWADDR || h->nlmsg_type == RTM_NEWROUTE)
|
||||
{
|
||||
while(sendto(daemon->srv_save->sfd->fd, daemon->packet, daemon->packet_len, 0,
|
||||
&daemon->srv_save->addr.sa, sa_len(&daemon->srv_save->addr)) == -1 && retry_send());
|
||||
break;
|
||||
}
|
||||
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(daemon, h);
|
||||
}
|
||||
}
|
||||
|
||||
static void nl_err(struct nlmsghdr *h)
|
||||
{
|
||||
struct nlmsgerr *err = NLMSG_DATA(h);
|
||||
if (err->error != 0)
|
||||
syslog(LOG_ERR, _("RTnetlink returns error: %s"), strerror(-(err->error)));
|
||||
}
|
||||
|
||||
/* 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. */
|
||||
static void nl_routechange(struct daemon *daemon, struct nlmsghdr *h)
|
||||
{
|
||||
if (h->nlmsg_type == RTM_NEWROUTE && daemon->srv_save)
|
||||
{
|
||||
struct rtmsg *rtm = NLMSG_DATA(h);
|
||||
if (rtm->rtm_type == RTN_UNICAST &&
|
||||
rtm->rtm_scope == RT_SCOPE_LINK)
|
||||
while(sendto(daemon->srv_save->sfd->fd, daemon->packet, daemon->packet_len, 0,
|
||||
&daemon->srv_save->addr.sa, sa_len(&daemon->srv_save->addr)) == -1 && retry_send());
|
||||
}
|
||||
}
|
||||
|
||||
void arp_inject(int fd, struct in_addr ip_addr, int iface,
|
||||
unsigned char *mac, unsigned int mac_len)
|
||||
{
|
||||
struct sockaddr_nl addr;
|
||||
struct {
|
||||
struct nlmsghdr nlh;
|
||||
struct ndmsg m;
|
||||
struct rtattr addr_attr;
|
||||
struct in_addr addr;
|
||||
struct rtattr ll_attr;
|
||||
char mac[DHCP_CHADDR_MAX];
|
||||
} req;
|
||||
|
||||
memset(&req, 0, sizeof(req));
|
||||
memset(&addr, 0, sizeof(addr));
|
||||
|
||||
addr.nl_family = AF_NETLINK;
|
||||
|
||||
req.nlh.nlmsg_len = sizeof(req);
|
||||
req.nlh.nlmsg_type = RTM_NEWNEIGH;
|
||||
req.nlh.nlmsg_flags = NLM_F_REQUEST | NLM_F_REPLACE | NLM_F_CREATE;
|
||||
|
||||
req.m.ndm_family = AF_INET;
|
||||
req.m.ndm_ifindex = iface;
|
||||
req.m.ndm_state = NUD_REACHABLE;
|
||||
|
||||
req.addr_attr.rta_type = NDA_DST;
|
||||
req.addr_attr.rta_len = RTA_LENGTH(sizeof(struct in_addr));
|
||||
req.addr = ip_addr;
|
||||
|
||||
req.ll_attr.rta_type = NDA_LLADDR;
|
||||
req.ll_attr.rta_len = RTA_LENGTH(mac_len);
|
||||
memcpy(req.mac, mac, mac_len);
|
||||
|
||||
while(sendto(fd, (void *)&req, sizeof(req), 0, (struct sockaddr *)&addr, sizeof(addr)) == -1 &&
|
||||
retry_send());
|
||||
}
|
||||
|
||||
#endif
|
||||
|
||||
|
||||
|
||||
Reference in New Issue
Block a user