usock: implement usock_inet_timeout() with RFC6555 support

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

diff --git a/usock.c b/usock.c
index 62a5f2067f9ffb890dd1b860a5e8d26a5ede7d1d..0ce5390434d2ccae31bd0d9ec49c7e74e2e47c23 100644 (file)
--- a/usock.c
+++ b/usock.c
@@ -28,8 +28,10 @@
 #include <string.h>
 #include <stdbool.h>
 #include <stdio.h>
+#include <poll.h>
 
 #include "usock.h"
+#include "utils.h"
 
 static void usock_set_flags(int sock, unsigned int type)
 {
@@ -81,7 +83,59 @@ static int usock_unix(int type, const char *host)
        return usock_connect(type, (struct sockaddr*)&sun, sizeof(sun), AF_UNIX, socktype, server);
 }
 
-int usock_inet(int type, const char *host, const char *service, void *addr)
+static int
+usock_inet_notimeout(int type, struct addrinfo *result, void *addr)
+{
+       struct addrinfo *rp;
+       int socktype = ((type & 0xff) == USOCK_TCP) ? SOCK_STREAM : SOCK_DGRAM;
+       bool server = !!(type & USOCK_SERVER);
+       int sock;
+
+       for (rp = result; rp != NULL; rp = rp->ai_next) {
+               sock = usock_connect(type, rp->ai_addr, rp->ai_addrlen, rp->ai_family, socktype, server);
+               if (sock >= 0) {
+                       if (addr)
+                               memcpy(addr, rp->ai_addr, rp->ai_addrlen);
+                       return sock;
+               }
+       }
+
+       return -1;
+}
+
+static int poll_restart(struct pollfd *fds, int nfds, int timeout)
+{
+       struct timespec ts, cur;
+       int msec = timeout % 1000;
+       int ret;
+
+       clock_gettime(CLOCK_MONOTONIC, &ts);
+
+       ts.tv_nsec += msec * 1000000;
+       if (ts.tv_nsec > 1000000000) {
+               ts.tv_sec++;
+               ts.tv_nsec -= 1000000000;
+       }
+       ts.tv_sec += timeout / 1000;
+
+       while (1) {
+               ret = poll(fds, nfds, timeout);
+               if (ret == EAGAIN)
+                       continue;
+
+               if (ret != EINTR)
+                       return ret;
+
+               clock_gettime(CLOCK_MONOTONIC, &cur);
+               timeout = (ts.tv_sec - cur.tv_sec) * 1000;
+               timeout += (ts.tv_nsec - cur.tv_nsec) / 1000000;
+               if (timeout <= 0)
+                       return 0;
+       }
+}
+
+int usock_inet_timeout(int type, const char *host, const char *service,
+                      void *addr, int timeout)
 {
        int socktype = ((type & 0xff) == USOCK_TCP) ? SOCK_STREAM : SOCK_DGRAM;
        bool server = !!(type & USOCK_SERVER);
@@ -94,20 +148,94 @@ int usock_inet(int type, const char *host, const char *service, void *addr)
                        | ((type & USOCK_SERVER) ? AI_PASSIVE : 0)
                        | ((type & USOCK_NUMERIC) ? AI_NUMERICHOST : 0),
        };
+       struct addrinfo *rp_v6 = NULL;
+       struct addrinfo *rp_v4 = NULL;
+       struct pollfd pfds[2] = {
+           { .fd = -1, .events = POLLOUT },
+           { .fd = -1, .events = POLLOUT },
+       };
        int sock = -1;
+       int i;
 
        if (getaddrinfo(host, service, &hints, &result))
                return -1;
 
+       if (timeout <= 0 || server) {
+               sock = usock_inet_notimeout(type, result, addr);
+               goto free_addrinfo;
+       }
+
        for (rp = result; rp != NULL; rp = rp->ai_next) {
-               sock = usock_connect(type, rp->ai_addr, rp->ai_addrlen, rp->ai_family, socktype, server);
-               if (sock >= 0) {
-                       if (addr)
-                               memcpy(addr, rp->ai_addr, rp->ai_addrlen);
-                       break;
+               if (rp->ai_family == AF_INET6 && !rp_v6)
+                       rp_v6 = rp;
+               if (rp->ai_family == AF_INET && !rp_v4)
+                       rp_v4 = rp;
+       }
+
+       if (!rp_v6 && !rp_v4)
+               goto out;
+
+       if (rp_v6) {
+               rp = rp_v6;
+               pfds[0].fd = usock_connect(type | USOCK_NONBLOCK, rp->ai_addr,
+                                          rp->ai_addrlen, rp->ai_family,
+                                          socktype, server);
+               if (pfds[0].fd < 0) {
+                       rp_v6 = NULL;
+                       goto try_v4;
                }
+
+               if (timeout > 300) {
+                       if (poll_restart(pfds, 1, 300) == 1) {
+                               rp = rp_v6;
+                               sock = pfds[0].fd;
+                               goto out;
+                       }
+               }
+               timeout -= 300;
+       }
+
+try_v4:
+       if (rp_v4) {
+               rp = rp_v4;
+               pfds[1].fd = usock_connect(type | USOCK_NONBLOCK, rp->ai_addr,
+                                                rp->ai_addrlen, rp->ai_family,
+                                                socktype, server);
+               if (pfds[1].fd < 0) {
+                       rp_v4 = NULL;
+                       if (!rp_v6)
+                               goto out;
+                       goto wait;
+               }
+       }
+
+wait:
+       poll_restart(pfds + !rp_v6, !!rp_v6 + !!rp_v4, timeout);
+       if (pfds[0].revents & POLLOUT) {
+               rp = rp_v6;
+               sock = pfds[0].fd;
+               goto out;
+       }
+
+       if (pfds[1].revents & POLLOUT) {
+               rp = rp_v4;
+               sock = pfds[1].fd;
+               goto out;
        }
 
+out:
+       for (i = 0; i < 2; i++) {
+               int fd = pfds[i].fd;
+               if (fd >= 0 && fd != sock)
+                       close(fd);
+       }
+
+       if (!(type & USOCK_NONBLOCK))
+               fcntl(sock, F_SETFL, fcntl(sock, F_GETFL) & ~O_NONBLOCK);
+
+       if (addr && sock >= 0)
+               memcpy(addr, rp->ai_addr, rp->ai_addrlen);
+free_addrinfo:
        freeaddrinfo(result);
        return sock;
 }

diff --git a/usock.h b/usock.h
index 2ead7e5fc4affdac19ccb2471970d300cd125bbc..5f2b84b092ce9ac17cde4645517fb1f9b3cc788a 100644 (file)
--- a/usock.h
+++ b/usock.h
@@ -32,7 +32,13 @@
 
 const char *usock_port(int port);
 int usock(int type, const char *host, const char *service);
-int usock_inet(int type, const char *host, const char *service, void *addr);
+int usock_inet_timeout(int type, const char *host, const char *service,
+                      void *addr, int timeout);
+static inline int
+usock_inet(int type, const char *host, const char *service, void *addr)
+{
+    return usock_inet_timeout(type, host, service, addr, -1);
+}
 
 /**
  * Wait for a socket to become ready.