1 files changed, 343 insertions, 0 deletions
diff --git a/lib/socket-util.c b/lib/socket-util.c
new file mode 100644
index 000000000..3d290e883
--- /dev/null
+++ b/lib/socket-util.c
@@ -0,0 +1,343 @@
+/*
+ * Copyright (c) 2008, 2009 Nicira Networks.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <config.h>
+#include "socket-util.h"
+#include <arpa/inet.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <netdb.h>
+#include <poll.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/resource.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include "fatal-signal.h"
+#include "util.h"
+
+#include "vlog.h"
+#define THIS_MODULE VLM_socket_util
+
+/* Sets 'fd' to non-blocking mode.  Returns 0 if successful, otherwise a
+ * positive errno value. */
+int
+set_nonblocking(int fd)
+{
+    int flags = fcntl(fd, F_GETFL, 0);
+    if (flags != -1) {
+        if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) != -1) {
+            return 0;
+        } else {
+            VLOG_ERR("fcntl(F_SETFL) failed: %s", strerror(errno));
+            return errno;
+        }
+    } else {
+        VLOG_ERR("fcntl(F_GETFL) failed: %s", strerror(errno));
+        return errno;
+    }
+}
+
+/* Returns the maximum valid FD value, plus 1. */
+int
+get_max_fds(void)
+{
+    static int max_fds = -1;
+    if (max_fds < 0) {
+        struct rlimit r;
+        if (!getrlimit(RLIMIT_NOFILE, &r)
+            && r.rlim_cur != RLIM_INFINITY
+            && r.rlim_cur != RLIM_SAVED_MAX
+            && r.rlim_cur != RLIM_SAVED_CUR) {
+            max_fds = r.rlim_cur;
+        } else {
+            VLOG_WARN("failed to obtain fd limit, defaulting to 1024");
+            max_fds = 1024;
+        }
+    }
+    return max_fds;
+}
+
+/* Translates 'host_name', which may be a DNS name or an IP address, into a
+ * numeric IP address in '*addr'.  Returns 0 if successful, otherwise a
+ * positive errno value. */
+int
+lookup_ip(const char *host_name, struct in_addr *addr) 
+{
+    if (!inet_aton(host_name, addr)) {
+        struct hostent *he = gethostbyname(host_name);
+        if (he == NULL) {
+            struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
+            VLOG_ERR_RL(&rl, "gethostbyname(%s): %s", host_name,
+                        (h_errno == HOST_NOT_FOUND ? "host not found"
+                         : h_errno == TRY_AGAIN ? "try again"
+                         : h_errno == NO_RECOVERY ? "non-recoverable error"
+                         : h_errno == NO_ADDRESS ? "no address"
+                         : "unknown error"));
+            return ENOENT;
+        }
+        addr->s_addr = *(uint32_t *) he->h_addr;
+    }
+    return 0;
+}
+
+/* Returns the error condition associated with socket 'fd' and resets the
+ * socket's error status. */
+int
+get_socket_error(int fd) 
+{
+    int error;
+    socklen_t len = sizeof(error);
+    if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &len) < 0) {
+        struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 10);
+        error = errno;
+        VLOG_ERR_RL(&rl, "getsockopt(SO_ERROR): %s", strerror(error));
+    }
+    return error;
+}
+
+int
+check_connection_completion(int fd) 
+{
+    struct pollfd pfd;
+    int retval;
+
+    pfd.fd = fd;
+    pfd.events = POLLOUT;
+    do {
+        retval = poll(&pfd, 1, 0);
+    } while (retval < 0 && errno == EINTR);
+    if (retval == 1) {
+        return get_socket_error(fd);
+    } else if (retval < 0) {
+        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 10);
+        VLOG_ERR_RL(&rl, "poll: %s", strerror(errno));
+        return errno;
+    } else {
+        return EAGAIN;
+    }
+}
+
+/* Drain all the data currently in the receive queue of a datagram socket (and
+ * possibly additional data).  There is no way to know how many packets are in
+ * the receive queue, but we do know that the total number of bytes queued does
+ * not exceed the receive buffer size, so we pull packets until none are left
+ * or we've read that many bytes. */
+int
+drain_rcvbuf(int fd)
+{
+    socklen_t rcvbuf_len;
+    size_t rcvbuf;
+
+    rcvbuf_len = sizeof rcvbuf;
+    if (getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf, &rcvbuf_len) < 0) {
+        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 10);
+        VLOG_ERR_RL(&rl, "getsockopt(SO_RCVBUF) failed: %s", strerror(errno));
+        return errno;
+    }
+    while (rcvbuf > 0) {
+        /* In Linux, specifying MSG_TRUNC in the flags argument causes the
+         * datagram length to be returned, even if that is longer than the
+         * buffer provided.  Thus, we can use a 1-byte buffer to discard the
+         * incoming datagram and still be able to account how many bytes were
+         * removed from the receive buffer.
+         *
+         * On other Unix-like OSes, MSG_TRUNC has no effect in the flags
+         * argument. */
+#ifdef __linux__
+#define BUFFER_SIZE 1
+#else
+#define BUFFER_SIZE 2048
+#endif
+        char buffer[BUFFER_SIZE];
+        ssize_t n_bytes = recv(fd, buffer, sizeof buffer,
+                               MSG_TRUNC | MSG_DONTWAIT);
+        if (n_bytes <= 0 || n_bytes >= rcvbuf) {
+            break;
+        }
+        rcvbuf -= n_bytes;
+    }
+    return 0;
+}
+
+/* Reads and discards up to 'n' datagrams from 'fd', stopping as soon as no
+ * more data can be immediately read.  ('fd' should therefore be in
+ * non-blocking mode.)*/
+void
+drain_fd(int fd, size_t n_packets)
+{
+    for (; n_packets > 0; n_packets--) {
+        /* 'buffer' only needs to be 1 byte long in most circumstances.  This
+         * size is defensive against the possibility that we someday want to
+         * use a Linux tap device without TUN_NO_PI, in which case a buffer
+         * smaller than sizeof(struct tun_pi) will give EINVAL on read. */
+        char buffer[128];
+        if (read(fd, buffer, sizeof buffer) <= 0) {
+            break;
+        }
+    }
+}
+
+/* Stores in '*un' a sockaddr_un that refers to file 'name'.  Stores in
+ * '*un_len' the size of the sockaddr_un. */
+static void
+make_sockaddr_un(const char *name, struct sockaddr_un* un, socklen_t *un_len)
+{
+    un->sun_family = AF_UNIX;
+    strncpy(un->sun_path, name, sizeof un->sun_path);
+    un->sun_path[sizeof un->sun_path - 1] = '\0';
+    *un_len = (offsetof(struct sockaddr_un, sun_path)
+                + strlen (un->sun_path) + 1);
+}
+
+/* Creates a Unix domain socket in the given 'style' (either SOCK_DGRAM or
+ * SOCK_STREAM) that is bound to '*bind_path' (if 'bind_path' is non-null) and
+ * connected to '*connect_path' (if 'connect_path' is non-null).  If 'nonblock'
+ * is true, the socket is made non-blocking.  If 'passcred' is true, the socket
+ * is configured to receive SCM_CREDENTIALS control messages.
+ *
+ * Returns the socket's fd if successful, otherwise a negative errno value. */
+int
+make_unix_socket(int style, bool nonblock, bool passcred UNUSED,
+                 const char *bind_path, const char *connect_path)
+{
+    int error;
+    int fd;
+
+    fd = socket(PF_UNIX, style, 0);
+    if (fd < 0) {
+        return -errno;
+    }
+
+    /* Set nonblocking mode right away, if we want it.  This prevents blocking
+     * in connect(), if connect_path != NULL.  (In turn, that's a corner case:
+     * it will only happen if style is SOCK_STREAM or SOCK_SEQPACKET, and only
+     * if a backlog of un-accepted connections has built up in the kernel.)  */
+    if (nonblock) {
+        int flags = fcntl(fd, F_GETFL, 0);
+        if (flags == -1) {
+            goto error;
+        }
+        if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) {
+            goto error;
+        }
+    }
+
+    if (bind_path) {
+        struct sockaddr_un un;
+        socklen_t un_len;
+        make_sockaddr_un(bind_path, &un, &un_len);
+        if (unlink(un.sun_path) && errno != ENOENT) {
+            VLOG_WARN("unlinking \"%s\": %s\n", un.sun_path, strerror(errno));
+        }
+        fatal_signal_add_file_to_unlink(bind_path);
+        if (bind(fd, (struct sockaddr*) &un, un_len)
+            || fchmod(fd, S_IRWXU)) {
+            goto error;
+        }
+    }
+
+    if (connect_path) {
+        struct sockaddr_un un;
+        socklen_t un_len;
+        make_sockaddr_un(connect_path, &un, &un_len);
+        if (connect(fd, (struct sockaddr*) &un, un_len)
+            && errno != EINPROGRESS) {
+            goto error;
+        }
+    }
+
+#ifdef SCM_CREDENTIALS
+    if (passcred) {
+        int enable = 1;
+        if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &enable, sizeof(enable))) {
+            goto error;
+        }
+    }
+#endif
+
+    return fd;
+
+error:
+    if (bind_path) {
+        fatal_signal_remove_file_to_unlink(bind_path);
+    }
+    error = errno;
+    close(fd);
+    return -error;
+}
+
+int
+get_unix_name_len(socklen_t sun_len)
+{
+    return (sun_len >= offsetof(struct sockaddr_un, sun_path)
+            ? sun_len - offsetof(struct sockaddr_un, sun_path)
+            : 0);
+}
+
+uint32_t
+guess_netmask(uint32_t ip)
+{
+    ip = ntohl(ip);
+    return ((ip >> 31) == 0 ? htonl(0xff000000)   /* Class A */
+            : (ip >> 30) == 2 ? htonl(0xffff0000) /* Class B */
+            : (ip >> 29) == 6 ? htonl(0xffffff00) /* Class C */
+            : htonl(0));                          /* ??? */
+}
+
+int
+read_fully(int fd, void *p_, size_t size, size_t *bytes_read)
+{
+    uint8_t *p = p_;
+
+    *bytes_read = 0;
+    while (size > 0) {
+        ssize_t retval = read(fd, p, size);
+        if (retval > 0) {
+            *bytes_read += retval;
+            size -= retval;
+            p += retval;
+        } else if (retval == 0) {
+            return EOF;
+        } else if (errno != EINTR) {
+            return errno;
+        }
+    }
+    return 0;
+}
+
+int
+write_fully(int fd, const void *p_, size_t size, size_t *bytes_written)
+{
+    const uint8_t *p = p_;
+
+    *bytes_written = 0;
+    while (size > 0) {
+        ssize_t retval = write(fd, p, size);
+        if (retval > 0) {
+            *bytes_written += retval;
+            size -= retval;
+            p += retval;
+        } else if (retval == 0) {
+            VLOG_WARN("write returned 0");
+            return EPROTO;
+        } else if (errno != EINTR) {
+            return errno;
+        }
+    }
+    return 0;
+}