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Use netlink when setting the default ipv4 gateway.

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This commit is contained in:
Nicholas J. Kain 2014-03-16 21:05:50 -04:00
parent 9de62e7b75
commit 8a24f74a11
1 changed files with 75 additions and 40 deletions
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115
ndhc/ifset.c
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@ -241,6 +241,58 @@ static ssize_t rtnl_addr_broadcast_send(int fd, int type, int ifa_flags,
return rtnl_do_send(fd, request, header->nlmsg_len, __func__); return rtnl_do_send(fd, request, header->nlmsg_len, __func__);
} }
static ssize_t rtnl_set_default_gw_v4(int fd, uint32_t gw4, int metric)
{
uint8_t request[NLMSG_ALIGN(sizeof(struct nlmsghdr)) +
NLMSG_ALIGN(sizeof(struct ifinfomsg)) +
RTA_LENGTH(sizeof(uint32_t))];
struct nlmsghdr *header;
struct rtmsg *rtmsg;
memset(&request, 0, sizeof request);
header = (struct nlmsghdr *)request;
header->nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
header->nlmsg_type = RTM_NEWROUTE;
header->nlmsg_flags = NLM_F_REPLACE | NLM_F_ACK | NLM_F_REQUEST;
header->nlmsg_seq = ifset_nl_seq++;
rtmsg = NLMSG_DATA(header);
rtmsg->rtm_family = AF_INET;
rtmsg->rtm_table = RT_TABLE_DEFAULT;
rtmsg->rtm_protocol = RTPROT_STATIC;
rtmsg->rtm_scope = RT_SCOPE_UNIVERSE;
rtmsg->rtm_type = RTN_UNICAST;
uint32_t dstaddr4 = 0;
if (nl_add_rtattr(header, sizeof request, RTA_DST,
&dstaddr4, sizeof dstaddr4) < 0) {
log_line("%s: (%s) couldn't add RTA_DST to nlmsg",
client_config.interface, __func__);
return -1;
}
if (nl_add_rtattr(header, sizeof request, RTA_OIF,
&client_config.ifindex,
sizeof client_config.ifindex) < 0) {
log_line("%s: (%s) couldn't add RTA_OIF to nlmsg",
client_config.interface, __func__);
return -1;
}
if (nl_add_rtattr(header, sizeof request, RTA_GATEWAY,
&gw4, sizeof gw4) < 0) {
log_line("%s: (%s) couldn't add RTA_GATEWAY to nlmsg",
client_config.interface, __func__);
return -1;
}
if (nl_add_rtattr(header, sizeof request, RTA_METRICS,
&metric, sizeof metric) < 0) {
log_line("%s: (%s) couldn't add RTA_METRICS to nlmsg",
client_config.interface, __func__);
return -1;
}
return rtnl_do_send(fd, request, header->nlmsg_len, __func__);
}
struct link_flag_data { struct link_flag_data {
int fd; int fd;
uint32_t flags; uint32_t flags;
@ -478,50 +530,33 @@ void perform_ip_subnet_bcast(const char *str_ipaddr,
} }
void perform_router(const char *str, size_t len) void perform_router(const char *str_router, size_t len)
{ {
struct rtentry rt; if (!str_router)
struct sockaddr_in *dest; return;
struct sockaddr_in *gateway; if (len < 7)
struct sockaddr_in *mask; return;
struct in_addr router; struct in_addr router;
int fd; if (inet_pton(AF_INET, str_router, &router) <= 0) {
log_line("%s: (%s) bad router ip address: '%s'",
if (!str) client_config.interface, __func__, str_router);
return;
if (len < 4)
return;
if (inet_pton(AF_INET, str, &router) <= 0)
return;
memset(&rt, 0, sizeof(struct rtentry));
dest = (struct sockaddr_in *) &rt.rt_dst;
dest->sin_family = AF_INET;
dest->sin_addr.s_addr = 0x00000000;
gateway = (struct sockaddr_in *) &rt.rt_gateway;
gateway->sin_family = AF_INET;
gateway->sin_addr = router;
mask = (struct sockaddr_in *) &rt.rt_genmask;
mask->sin_family = AF_INET;
mask->sin_addr.s_addr = 0x00000000;
rt.rt_flags = RTF_UP | RTF_GATEWAY;
if (mask->sin_addr.s_addr == 0xffffffff) rt.rt_flags |= RTF_HOST;
rt.rt_dev = client_config.interface;
rt.rt_metric = 1;
fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd == -1) {
log_line("%s: (perform_router) failed to open interface socket: %s",
client_config.interface, strerror(errno));
return; return;
} }
if (ioctl(fd, SIOCADDRT, &rt)) {
if (errno != EEXIST) int fd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
log_line("%s: failed to set route: %s", if (fd < 0) {
client_config.interface, strerror(errno)); log_line("%s: (%s) netlink socket open failed: %s",
} else client_config.interface, __func__, strerror(errno));
log_line("Gateway router set to: '%s'", str); return;
}
// XXX: Probably need to clear out the old default gw.
if (rtnl_set_default_gw_v4(fd, router.s_addr, 1) < 0)
log_line("%s: (%s) failed to set route: %s",
client_config.interface, __func__, strerror(errno));
else
log_line("Gateway router set to: '%s'", str_router);
close(fd); close(fd);
} }