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Implement GetDefaultRoute on Linux

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This commit is contained in:
Ludvig Strigeus 2018-08-09 14:36:45 +02:00
parent f8bf85219b
commit 1a7ba8683e
1 changed files with 92 additions and 3 deletions
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95
network_bsd_common.cpp
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@ -38,6 +38,7 @@
#include <linux/if.h>
#include <linux/if_tun.h>
#include <sys/prctl.h>
#include <linux/rtnetlink.h>
#endif
void SetThreadName(const char *name) {
@ -149,8 +150,94 @@ static bool GetDefaultRoute(char *iface, size_t iface_size, uint32 *gw_addr) {
#endif // defined(OS_MACOSX) || defined(OS_FREEBSD)
#if defined(OS_LINUX)
struct LinuxParsedRoute {
int has;
struct in_addr dst, gateway;
char ifname[IF_NAMESIZE];
};
static bool ParseLinuxRoutes(struct nlmsghdr *nl, struct LinuxParsedRoute *result) {
struct rtmsg *rt = (struct rtmsg *)NLMSG_DATA(nl);
if (rt->rtm_family != AF_INET || rt->rtm_table != RT_TABLE_MAIN)
return false;
struct rtattr *attr = (struct rtattr *)RTM_RTA(rt);
int len = RTM_PAYLOAD(nl);
int has = 0;
for(; RTA_OK(attr, len); attr = RTA_NEXT(attr, len)) {
switch(attr->rta_type) {
case RTA_OIF:
has |= 1;
if_indextoname(*(int *)RTA_DATA(attr), result->ifname);
break;
case RTA_GATEWAY:
has |= 2;
memcpy(&result->gateway, RTA_DATA(attr), sizeof(result->gateway));
break;
case RTA_DST:
has |= 4;
memcpy(&result->dst, RTA_DATA(attr), sizeof(result->dst));
break;
}
}
result->has = has;
return true;
}
static bool GetDefaultRoute(char *iface, size_t iface_size, uint32 *gw_addr) {
return false;
enum {BUFSIZE = 8192};
struct nlmsghdr *nl;
struct rtmsg *rt;
struct LinuxParsedRoute parsed_route;
char buffer[BUFSIZE];
int fd, len, pid = getpid();
bool result = false;
if ((fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE)) < 0)
return false;
size_t msg_size = NLMSG_SPACE(sizeof(struct rtmsg));
memset(buffer, 0, msg_size);
nl = (struct nlmsghdr *)buffer;
nl->nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
nl->nlmsg_type = RTM_GETROUTE;
nl->nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST;
nl->nlmsg_seq = 1;
nl->nlmsg_pid = pid;
rt = (struct rtmsg *)NLMSG_DATA(nl);
rt->rtm_family = AF_INET;
rt->rtm_table = RT_TABLE_MAIN;
if (send(fd, nl, msg_size, 0) != msg_size) {
RERROR("write to route socket failed");
goto done;
}
do {
if ((len = recv(fd, buffer, BUFSIZE, 0)) < 0) {
RERROR("read from route socket failed");
goto done;
}
for (nl = (struct nlmsghdr *)buffer; NLMSG_OK(nl, len); nl = NLMSG_NEXT(nl, len)) {
if (nl->nlmsg_seq != 1 || nl->nlmsg_pid != pid)
continue;
if (nl->nlmsg_type == NLMSG_DONE)
goto done;
if (nl->nlmsg_type == NLMSG_ERROR) {
RERROR("Error in recieved packet");
goto done;
}
if (ParseLinuxRoutes(nl, &parsed_route) && (parsed_route.has & (1+2+4)) == (1+2)) {
size_t l = strlen(parsed_route.ifname);
if (l < iface_size) {
*gw_addr = ReadBE32(&parsed_route.gateway);
memcpy(iface, parsed_route.ifname, l + 1);
result = true;
}
}
}
} while ((nl->nlmsg_flags & NLM_F_MULTI) != 0);
done:
close(fd);
return result;
}
#endif // defined(OS_LINUX)
@ -367,9 +454,11 @@ static void AddOrRemoveRoute(const RouteInfo &cd, bool remove) {
#if defined(OS_LINUX)
const char *cmd = remove ? "delete" : "add";
if (cd.family == AF_INET) {
RunCommand("/sbin/route %s -net %s gw %s", cmd, buf1, buf2);
const char *net_or_host = (cd.cidr == 32) ? "-host" : "-net";
RunCommand("/sbin/route %s %s %s gw %s", cmd, net_or_host, buf1, buf2);
} else {
RunCommand("/sbin/route %s -net inet6 %s gw %s", cmd, buf1, buf2);
const char *net_or_host = (cd.cidr == 128) ? "-host" : "-net";
RunCommand("/sbin/route %s %s inet6 %s gw %s", cmd, net_or_host, buf1, buf2);
}
#elif defined(OS_MACOSX) || defined(OS_FREEBSD)
const char *cmd = remove ? "delete" : "add";