Merge branch 'hostfwd-unix' into 'master'

Support Unix sockets in hostfwd

See merge request slirp/libslirp!103

2 files changed, 156 insertions, 8 deletions

diff --git a/src/socket.c b/src/socket.c
index 9e1e47e..f071d69 100644
--- a/src/socket.c
+++ b/src/socket.c
@@ -51,6 +51,7 @@ struct socket *socreate(Slirp *slirp, int type)
     so->so_type = type;
     so->so_state = SS_NOFDREF;
     so->s = -1;
+    so->s_aux = -1;
     so->slirp = slirp;
     so->pollfds_idx = -1;
 
@@ -83,6 +84,10 @@ void sofree(struct socket *so)
 {
     Slirp *slirp = so->slirp;
 
+    if (so->s_aux != -1) {
+        closesocket(so->s_aux);
+    }
+
     soqfree(so, &slirp->if_fastq);
     soqfree(so, &slirp->if_batchq);
 
@@ -774,14 +779,35 @@ struct socket *tcpx_listen(Slirp *slirp,
     char addrstr[INET6_ADDRSTRLEN];
     char portstr[6];
     int ret;
-    ret = getnameinfo(haddr, haddrlen, addrstr, sizeof(addrstr), portstr, sizeof(portstr), NI_NUMERICHOST|NI_NUMERICSERV);
-    g_assert(ret == 0);
-    DEBUG_ARG("haddr = %s", addrstr);
-    DEBUG_ARG("hport = %s", portstr);
-    ret = getnameinfo(laddr, laddrlen, addrstr, sizeof(addrstr), portstr, sizeof(portstr), NI_NUMERICHOST|NI_NUMERICSERV);
-    g_assert(ret == 0);
-    DEBUG_ARG("laddr = %s", addrstr);
-    DEBUG_ARG("lport = %s", portstr);
+    switch (haddr->sa_family) {
+    case AF_INET:
+    case AF_INET6:
+        ret = getnameinfo(haddr, haddrlen, addrstr, sizeof(addrstr), portstr, sizeof(portstr), NI_NUMERICHOST|NI_NUMERICSERV);
+        g_assert(ret == 0);
+        DEBUG_ARG("hfamily = INET");
+        DEBUG_ARG("haddr = %s", addrstr);
+        DEBUG_ARG("hport = %s", portstr);
+        break;
+#ifndef _WIN32
+    case AF_UNIX:
+        DEBUG_ARG("hfamily = UNIX");
+        DEBUG_ARG("hpath = %s", ((struct sockaddr_un *) haddr)->sun_path);
+        break;
+#endif
+    default:
+        g_assert_not_reached();
+    }
+    switch (laddr->sa_family) {
+    case AF_INET:
+    case AF_INET6:
+        ret = getnameinfo(laddr, laddrlen, addrstr, sizeof(addrstr), portstr, sizeof(portstr), NI_NUMERICHOST|NI_NUMERICSERV);
+        g_assert(ret == 0);
+        DEBUG_ARG("laddr = %s", addrstr);
+        DEBUG_ARG("lport = %s", portstr);
+        break;
+    default:
+        g_assert_not_reached();
+    }
     DEBUG_ARG("flags = %x", flags);
 
     /*
@@ -1042,6 +1068,109 @@ void sotranslate_accept(struct socket *so)
         }
         break;
 
+    case AF_UNIX: {
+        /* Translate Unix socket to random ephemeral source port. We obtain
+         * this source port by binding to port 0 so that the OS allocates a
+         * port for us. If this fails, we fall back to choosing a random port
+         * with a random number generator. */
+        int s;
+        struct sockaddr_in in_addr;
+        struct sockaddr_in6 in6_addr;
+        socklen_t in_addr_len;
+
+        if (so->slirp->in_enabled) {
+            so->so_ffamily = AF_INET;
+            so->so_faddr = slirp->vhost_addr;
+            so->so_fport = 0;
+
+            // TODO Is there a better way of checking socket type?
+            switch (so->so_type) {
+            case IPPROTO_TCP:
+                s = slirp_socket(PF_INET, SOCK_STREAM, 0);
+                break;
+            case IPPROTO_UDP:
+                s = slirp_socket(PF_INET, SOCK_DGRAM, 0);
+                break;
+            default:
+                g_assert_not_reached();
+                break;
+            }
+            if (s < 0) {
+                g_error("Ephemeral slirp_socket() allocation failed");
+                goto unix2inet_cont;
+            }
+            memset(&in_addr, 0, sizeof(in_addr));
+            in_addr.sin_family = AF_INET;
+            in_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+            in_addr.sin_port = htons(0);
+            if (bind(s, (struct sockaddr *) &in_addr, sizeof(in_addr))) {
+                g_error("Ephemeral bind() failed");
+                closesocket(s);
+                goto unix2inet_cont;
+            }
+            in_addr_len = sizeof(in_addr);
+            if (getsockname(s, (struct sockaddr *) &in_addr, &in_addr_len)) {
+                g_error("Ephemeral getsockname() failed");
+                closesocket(s);
+                goto unix2inet_cont;
+            }
+            so->s_aux = s;
+            so->so_fport = in_addr.sin_port;
+
+unix2inet_cont:
+            if (!so->so_fport) {
+                g_warning("Falling back to random port allocation");
+                so->so_fport = htons(g_rand_int_range(slirp->grand, 49152, 65536));
+            }
+        } else if (so->slirp->in6_enabled) {
+            so->so_ffamily = AF_INET6;
+            so->so_faddr6 = slirp->vhost_addr6;
+            so->so_fport6 = 0;
+
+            switch (so->so_type) {
+            case IPPROTO_TCP:
+                s = slirp_socket(PF_INET6, SOCK_STREAM, 0);
+                break;
+            case IPPROTO_UDP:
+                s = slirp_socket(PF_INET6, SOCK_DGRAM, 0);
+                break;
+            default:
+                g_assert_not_reached();
+                break;
+            }
+            if (s < 0) {
+                g_error("Ephemeral slirp_socket() allocation failed");
+                goto unix2inet6_cont;
+            }
+            memset(&in6_addr, 0, sizeof(in6_addr));
+            in6_addr.sin6_family = AF_INET6;
+            in6_addr.sin6_addr = in6addr_loopback;
+            in6_addr.sin6_port = htons(0);
+            if (bind(s, (struct sockaddr *) &in6_addr, sizeof(in6_addr))) {
+                g_error("Ephemeral bind() failed");
+                closesocket(s);
+                goto unix2inet6_cont;
+            }
+            in_addr_len = sizeof(in6_addr);
+            if (getsockname(s, (struct sockaddr *) &in6_addr, &in_addr_len)) {
+                g_error("Ephemeral getsockname() failed");
+                closesocket(s);
+                goto unix2inet6_cont;
+            }
+            so->s_aux = s;
+            so->so_fport6 = in6_addr.sin6_port;
+
+unix2inet6_cont:
+            if (!so->so_fport6) {
+                g_warning("Falling back to random port allocation");
+                so->so_fport6 = htons(g_rand_int_range(slirp->grand, 49152, 65536));
+            }
+        } else {
+            g_assert_not_reached();
+        }
+        break;
+    } /* case AF_UNIX */
+
     default:
         break;
     }
diff --git a/src/socket.h b/src/socket.h
index acafff0..ca8c103 100644
--- a/src/socket.h
+++ b/src/socket.h
@@ -6,6 +6,12 @@
 #ifndef SLIRP_SOCKET_H
 #define SLIRP_SOCKET_H
 
+#include <string.h>
+
+#ifndef _WIN32
+#include <sys/un.h>
+#endif
+
 #include "misc.h"
 #include "sbuf.h"
 
@@ -34,6 +40,8 @@ struct socket {
     struct socket *so_next, *so_prev; /* For a linked list of sockets */
 
     int s; /* The actual socket */
+    int s_aux; /* An auxiliary socket for miscellaneous use. Currently used to
+                * reserve OS ports in UNIX-to-inet translation. */
     struct gfwd_list *guestfwd;
 
     int pollfds_idx; /* GPollFD GArray index */
@@ -129,6 +137,13 @@ static inline int sockaddr_equal(const struct sockaddr_storage *a,
         return (in6_equal(&a6->sin6_addr, &b6->sin6_addr) &&
                 a6->sin6_port == b6->sin6_port);
     }
+#ifndef _WIN32
+    case AF_UNIX: {
+        const struct sockaddr_un *aun = (const struct sockaddr_un *)a;
+        const struct sockaddr_un *bun = (const struct sockaddr_un *)b;
+        return strncmp(aun->sun_path, bun->sun_path, sizeof(aun->sun_path)) == 0;
+    }
+#endif
     default:
         g_assert_not_reached();
     }
@@ -143,6 +158,10 @@ static inline socklen_t sockaddr_size(const struct sockaddr_storage *a)
         return sizeof(struct sockaddr_in);
     case AF_INET6:
         return sizeof(struct sockaddr_in6);
+#ifndef _WIN32
+    case AF_UNIX:
+        return sizeof(struct sockaddr_un);
+#endif
     default:
         g_assert_not_reached();
     }