[Qemu-devel] [PATCH 1/4] Use getaddrinfo for migration

[Amos Kong <akong@redhat.com>]

This allows us to use ipv4/ipv6 for migration addresses.
Once there, it also uses /etc/services names (it came free).

Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Amos Kong <akong@redhat.com>
---
 migration-tcp.c |   60 ++++++++-----------------------
 net.c           |  108 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 qemu_socket.h   |    3 ++
 3 files changed, 127 insertions(+), 44 deletions(-)

diff --git a/migration-tcp.c b/migration-tcp.c
index 35a5781..644bb8f 100644
--- a/migration-tcp.c
+++ b/migration-tcp.c
@@ -81,43 +81,27 @@ static void tcp_wait_for_connect(void *opaque)
 
 int tcp_start_outgoing_migration(MigrationState *s, const char *host_port)
 {
-    struct sockaddr_in addr;
     int ret;
-
-    ret = parse_host_port(&addr, host_port);
-    if (ret < 0) {
-        return ret;
-    }
+    int fd;
 
     s->get_error = socket_errno;
     s->write = socket_write;
     s->close = tcp_close;
 
-    s->fd = qemu_socket(PF_INET, SOCK_STREAM, 0);
-    if (s->fd == -1) {
-        DPRINTF("Unable to open socket");
-        return -socket_error();
-    }
-
-    socket_set_nonblock(s->fd);
-
-    do {
-        ret = connect(s->fd, (struct sockaddr *)&addr, sizeof(addr));
-        if (ret == -1) {
-            ret = -socket_error();
-        }
-        if (ret == -EINPROGRESS || ret == -EWOULDBLOCK) {
-            qemu_set_fd_handler2(s->fd, NULL, NULL, tcp_wait_for_connect, s);
-            return 0;
-        }
-    } while (ret == -EINTR);
-
-    if (ret < 0) {
+    ret = tcp_client_start(host_port, &fd);
+    s->fd = fd;
+    if (ret == -EINPROGRESS || ret == -EWOULDBLOCK) {
+        DPRINTF("connect in progress");
+        qemu_set_fd_handler2(s->fd, NULL, NULL, tcp_wait_for_connect, s);
+    } else if (ret < 0) {
         DPRINTF("connect failed\n");
-        migrate_fd_error(s);
+        if (ret != -EINVAL) {
+            migrate_fd_error(s);
+        }
         return ret;
+    } else {
+        migrate_fd_connect(s);
     }
-    migrate_fd_connect(s);
     return 0;
 }
 
@@ -157,28 +141,16 @@ out2:
 
 int tcp_start_incoming_migration(const char *host_port)
 {
-    struct sockaddr_in addr;
-    int val;
+    int ret;
     int s;
 
     DPRINTF("Attempting to start an incoming migration\n");
 
-    if (parse_host_port(&addr, host_port) < 0) {
-        fprintf(stderr, "invalid host/port combination: %s\n", host_port);
-        return -EINVAL;
-    }
-
-    s = qemu_socket(PF_INET, SOCK_STREAM, 0);
-    if (s == -1) {
-        return -socket_error();
+    ret = tcp_server_start(host_port, &s);
+    if (ret < 0) {
+        return ret;
     }
 
-    val = 1;
-    setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (const char *)&val, sizeof(val));
-
-    if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
-        goto err;
-    }
     if (listen(s, 1) == -1) {
         goto err;
     }
diff --git a/net.c b/net.c
index c34474f..f63014c 100644
--- a/net.c
+++ b/net.c
@@ -99,6 +99,114 @@ static int get_str_sep(char *buf, int buf_size, const char **pp, int sep)
     return 0;
 }
 
+static int tcp_server_bind(int fd, struct addrinfo *rp)
+{
+    int ret;
+    int val = 1;
+
+    /* allow fast reuse */
+    setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (const char *)&val, sizeof(val));
+
+    ret = bind(fd, rp->ai_addr, rp->ai_addrlen);
+
+    if (ret == -1) {
+        ret = -socket_error();
+    }
+    return ret;
+
+}
+
+static int tcp_client_connect(int fd, struct addrinfo *rp)
+{
+    int ret;
+
+    do {
+        ret = connect(fd, rp->ai_addr, rp->ai_addrlen);
+        if (ret == -1) {
+            ret = -socket_error();
+        }
+    } while (ret == -EINTR);
+
+    return ret;
+}
+
+
+static int tcp_start_common(const char *str, int *fd, bool server)
+{
+    char hostname[512];
+    const char *service;
+    const char *name;
+    struct addrinfo hints;
+    struct addrinfo *result, *rp;
+    int s;
+    int sfd;
+    int ret = -EINVAL;
+
+    *fd = -1;
+    service = str;
+    if (get_str_sep(hostname, sizeof(hostname), &service, ':') < 0) {
+        return -EINVAL;
+    }
+    if (server && strlen(hostname) == 0) {
+        name = NULL;
+    } else {
+        name = hostname;
+    }
+
+    /* Obtain address(es) matching host/port */
+
+    memset(&hints, 0, sizeof(struct addrinfo));
+    hints.ai_family = AF_UNSPEC;     /* Allow IPv4 or IPv6 */
+    hints.ai_socktype = SOCK_STREAM; /* Datagram socket */
+
+    if (server) {
+        hints.ai_flags = AI_PASSIVE;
+    }
+
+    s = getaddrinfo(name, service, &hints, &result);
+    if (s != 0) {
+        fprintf(stderr, "qemu: getaddrinfo: %s\n", gai_strerror(s));
+        return -EINVAL;
+    }
+
+    /* getaddrinfo() returns a list of address structures.
+       Try each address until we successfully bind/connect).
+       If socket(2) (or bind/connect(2)) fails, we (close the socket
+       and) try the next address. */
+
+    for (rp = result; rp != NULL; rp = rp->ai_next) {
+        sfd = qemu_socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+        if (sfd == -1) {
+            ret = -errno;
+            continue;
+        }
+        socket_set_nonblock(sfd);
+        if (server) {
+            ret = tcp_server_bind(sfd, rp);
+        } else {
+            ret = tcp_client_connect(sfd, rp);
+        }
+        if (ret >= 0 || ret == -EINPROGRESS || ret == -EWOULDBLOCK) {
+            *fd = sfd;
+            break;                  /* Success */
+        }
+        close(sfd);
+    }
+
+    freeaddrinfo(result);
+    return ret;
+}
+
+int tcp_server_start(const char *str, int *fd)
+{
+    return tcp_start_common(str, fd, true);
+}
+
+int tcp_client_start(const char *str, int *fd)
+{
+    return tcp_start_common(str, fd, false);
+}
+
 int parse_host_port(struct sockaddr_in *saddr, const char *str)
 {
     char buf[512];
diff --git a/qemu_socket.h b/qemu_socket.h
index fe4cf6c..6024496 100644
--- a/qemu_socket.h
+++ b/qemu_socket.h
@@ -58,4 +58,7 @@ int unix_connect(const char *path);
 int parse_host_port(struct sockaddr_in *saddr, const char *str);
 int socket_init(void);
 
+int tcp_client_start(const char *str, int *fd);
+int tcp_server_start(const char *str, int *fd);
+
 #endif /* QEMU_SOCKET_H */