tinyproxy/src/sock.c

/* tinyproxy - A fast light-weight HTTP proxy
 * Copyright (C) 1998 Steven Young <sdyoung@miranda.org>
 * Copyright (C) 1999, 2004 Robert James Kaes <rjkaes@users.sourceforge.net>
 * Copyright (C) 2000 Chris Lightfoot <chris@ex-parrot.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

/* Sockets are created and destroyed here. When a new connection comes in from
 * a client, we need to copy the socket and the create a second socket to the
 * remote server the client is trying to connect to. Also, the listening
 * socket is created and destroyed here. Sounds more impressive than it
 * actually is.
 */

#include "tinyproxy.h"

#include "log.h"
#include "heap.h"
#include "network.h"
#include "sock.h"
#include "text.h"

/*
 * Bind the given socket to the supplied address.  The socket is
 * returned if the bind succeeded.  Otherwise, -1 is returned
 * to indicate an error.
 */
static int
bind_socket(int sockfd, const char *addr)
{
        struct addrinfo hints, *res, *ressave;

        assert(sockfd >= 0);
        assert(addr != NULL && strlen(addr) != 0);

        memset(&hints, 0, sizeof(struct addrinfo));
        hints.ai_family = AF_UNSPEC;
        hints.ai_socktype = SOCK_STREAM;

        /* The local port it not important */
        if (getaddrinfo(addr, NULL, &hints, &res) != 0)
                return -1;

        ressave = res;

        /* Loop through the addresses and try to bind to each */
        do {
                if (bind(sockfd, res->ai_addr, res->ai_addrlen) == 0)
                        break;  /* success */
        } while ((res = res->ai_next) != NULL);

        freeaddrinfo(ressave);
        if (res == NULL)        /* was not able to bind to any address */
                return -1;

        return sockfd;
}

/*
 * Open a connection to a remote host.  It's been re-written to use
 * the getaddrinfo() library function, which allows for a protocol
 * independent implementation (mostly for IPv4 and IPv6 addresses.)
 */
int
opensock(const char *host, int port, const char *bind_to)
{
        int sockfd, n;
        struct addrinfo hints, *res, *ressave;
        char portstr[6];

        assert(host != NULL);
        assert(port > 0);

        memset(&hints, 0, sizeof(struct addrinfo));
        hints.ai_family = AF_UNSPEC;
        hints.ai_socktype = SOCK_STREAM;

        snprintf(portstr, sizeof(portstr), "%d", port);

        n = getaddrinfo(host, portstr, &hints, &res);
        if (n != 0) {
                log_message(LOG_ERR, "opensock: Could not retrieve info for %s",
                            host);
                return -1;
        }

        ressave = res;
        do {
                sockfd =
                    socket(res->ai_family, res->ai_socktype, res->ai_protocol);
                if (sockfd < 0)
                        continue;       /* ignore this one */

                /* Bind to the specified address */
                if (bind_to) {
                        if (bind_socket(sockfd, bind_to) < 0) {
                                close(sockfd);
                                continue;       /* can't bind, so try again */
                        }
                } else if (config.bind_address) {
                        if (bind_socket(sockfd, config.bind_address) < 0) {
                                close(sockfd);
                                continue;       /* can't bind, so try again */
                        }
                }

                if (connect(sockfd, res->ai_addr, res->ai_addrlen) == 0)
                        break;  /* success */

                close(sockfd);
        } while ((res = res->ai_next) != NULL);

        freeaddrinfo(ressave);
        if (res == NULL) {
                log_message(LOG_ERR,
                            "opensock: Could not establish a connection to %s",
                            host);
                return -1;
        }

        return sockfd;
}

/*
 * Set the socket to non blocking -rjkaes
 */
int
socket_nonblocking(int sock)
{
        int flags;

        assert(sock >= 0);

        flags = fcntl(sock, F_GETFL, 0);
        return fcntl(sock, F_SETFL, flags | O_NONBLOCK);
}

/*
 * Set the socket to blocking -rjkaes
 */
int
socket_blocking(int sock)
{
        int flags;

        assert(sock >= 0);

        flags = fcntl(sock, F_GETFL, 0);
        return fcntl(sock, F_SETFL, flags & ~O_NONBLOCK);
}

/*
 * Start listening to a socket. Create a socket with the selected port.
 * The size of the socket address will be returned to the caller through
 * the pointer, while the socket is returned as a default return.
 *	- rjkaes
 */
int
listen_sock(uint16_t port, socklen_t * addrlen)
{
        int listenfd;
        const int on = 1;
        struct sockaddr_in addr;

        assert(port > 0);
        assert(addrlen != NULL);

        listenfd = socket(AF_INET, SOCK_STREAM, 0);
        setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));

        memset(&addr, 0, sizeof(addr));
        addr.sin_family = AF_INET;
        addr.sin_port = htons(port);

        if (config.ipAddr) {
                addr.sin_addr.s_addr = inet_addr(config.ipAddr);
        } else {
                addr.sin_addr.s_addr = inet_addr("0.0.0.0");
        }

        if (bind(listenfd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
                log_message(LOG_ERR,
                            "Unable to bind listening socket because of %s",
                            strerror(errno));
                return -1;
        }

        if (listen(listenfd, MAXLISTEN) < 0) {
                log_message(LOG_ERR,
                            "Unable to start listening socket because of %s",
                            strerror(errno));
                return -1;
        }

        *addrlen = sizeof(addr);

        return listenfd;
}

/*
 * Takes a socket descriptor and returns the socket's IP address.
 */
int
getsock_ip(int fd, char *ipaddr)
{
        struct sockaddr_storage name;
        socklen_t namelen = sizeof(name);

        assert(fd >= 0);

        if (getsockname(fd, (struct sockaddr *)&name, &namelen) != 0) {
                log_message(LOG_ERR, "getsock_ip: getsockname() error: %s",
                            strerror(errno));
                return -1;
        }

        if (get_ip_string((struct sockaddr *)&name, ipaddr, IP_LENGTH) == NULL)
                return -1;

        return 0;
}

/*
 * Return the peer's socket information.
 */
int
getpeer_information(int fd, char *ipaddr, char *string_addr)
{
        struct sockaddr_storage sa;
        socklen_t salen = sizeof sa;

        assert(fd >= 0);
        assert(ipaddr != NULL);
        assert(string_addr != NULL);

        /* Set the strings to default values */
        ipaddr[0] = '\0';
        strlcpy(string_addr, "[unknown]", HOSTNAME_LENGTH);

        /* Look up the IP address */
        if (getpeername(fd, (struct sockaddr *) &sa, &salen) != 0)
                return -1;

        if (get_ip_string((struct sockaddr *)&sa, ipaddr, IP_LENGTH) == NULL)
                return -1;

        /* Get the full host name */
        return getnameinfo((struct sockaddr *)&sa, salen,
                           string_addr, HOSTNAME_LENGTH, NULL, 0, 0);
}