wpa_ctrl.c

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/*
 * wpa_supplicant/hostapd control interface library
 * Copyright (c) 2004-2007, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#ifdef CONFIG_CTRL_IFACE

#ifdef CONFIG_CTRL_IFACE_UNIX
#include <sys/un.h>
#endif /* CONFIG_CTRL_IFACE_UNIX */

#include "wpa_ctrl.h"
#include "common.h"


#if defined(CONFIG_CTRL_IFACE_UNIX) || defined(CONFIG_CTRL_IFACE_UDP)
#define CTRL_IFACE_SOCKET
#endif /* CONFIG_CTRL_IFACE_UNIX || CONFIG_CTRL_IFACE_UDP */


struct wpa_ctrl {
#ifdef CONFIG_CTRL_IFACE_UDP
        int s;
        struct sockaddr_in local;
        struct sockaddr_in dest;
        char *cookie;
#endif /* CONFIG_CTRL_IFACE_UDP */
#ifdef CONFIG_CTRL_IFACE_UNIX
        int s;
        struct sockaddr_un local;
        struct sockaddr_un dest;
#endif /* CONFIG_CTRL_IFACE_UNIX */
#ifdef CONFIG_CTRL_IFACE_NAMED_PIPE
        HANDLE pipe;
#endif /* CONFIG_CTRL_IFACE_NAMED_PIPE */
};


#ifdef CONFIG_CTRL_IFACE_UNIX

struct wpa_ctrl * wpa_ctrl_open(const char *ctrl_path)
{
        struct wpa_ctrl *ctrl;
        static int counter = 0;
        int ret;
        size_t res;
        int tries = 0;

        ctrl = os_malloc(sizeof(*ctrl));
        if (ctrl == NULL)
                return NULL;
        os_memset(ctrl, 0, sizeof(*ctrl));

        ctrl->s = socket(PF_UNIX, SOCK_DGRAM, 0);
        if (ctrl->s < 0) {
                os_free(ctrl);
                return NULL;
        }

        ctrl->local.sun_family = AF_UNIX;
        counter++;
try_again:
        ret = os_snprintf(ctrl->local.sun_path, sizeof(ctrl->local.sun_path),
                          "/tmp/wpa_ctrl_%d-%d", getpid(), counter);
        if (ret < 0 || (size_t) ret >= sizeof(ctrl->local.sun_path)) {
                close(ctrl->s);
                os_free(ctrl);
                return NULL;
        }
        tries++;
        if (bind(ctrl->s, (struct sockaddr *) &ctrl->local,
                    sizeof(ctrl->local)) < 0) {
                if (errno == EADDRINUSE && tries < 2) {
                        /*
                         * getpid() returns unique identifier for this instance
                         * of wpa_ctrl, so the existing socket file must have
                         * been left by unclean termination of an earlier run.
                         * Remove the file and try again.
                         */
                        unlink(ctrl->local.sun_path);
                        goto try_again;
                }
                close(ctrl->s);
                os_free(ctrl);
                return NULL;
        }

        ctrl->dest.sun_family = AF_UNIX;
        res = os_strlcpy(ctrl->dest.sun_path, ctrl_path,
                         sizeof(ctrl->dest.sun_path));
        if (res >= sizeof(ctrl->dest.sun_path)) {
                close(ctrl->s);
                os_free(ctrl);
                return NULL;
        }
        if (connect(ctrl->s, (struct sockaddr *) &ctrl->dest,
                    sizeof(ctrl->dest)) < 0) {
                close(ctrl->s);
                unlink(ctrl->local.sun_path);
                os_free(ctrl);
                return NULL;
        }

        return ctrl;
}


void wpa_ctrl_close(struct wpa_ctrl *ctrl)
{
        unlink(ctrl->local.sun_path);
        close(ctrl->s);
        os_free(ctrl);
}

#endif /* CONFIG_CTRL_IFACE_UNIX */


#ifdef CONFIG_CTRL_IFACE_UDP

struct wpa_ctrl * wpa_ctrl_open(const char *ctrl_path)
{
        struct wpa_ctrl *ctrl;
        char buf[128];
        size_t len;

        ctrl = os_malloc(sizeof(*ctrl));
        if (ctrl == NULL)
                return NULL;
        os_memset(ctrl, 0, sizeof(*ctrl));

        ctrl->s = socket(PF_INET, SOCK_DGRAM, 0);
        if (ctrl->s < 0) {
                perror("socket");
                os_free(ctrl);
                return NULL;
        }

        ctrl->local.sin_family = AF_INET;
        ctrl->local.sin_addr.s_addr = htonl((127 << 24) | 1);
        if (bind(ctrl->s, (struct sockaddr *) &ctrl->local,
                 sizeof(ctrl->local)) < 0) {
                close(ctrl->s);
                os_free(ctrl);
                return NULL;
        }

        ctrl->dest.sin_family = AF_INET;
        ctrl->dest.sin_addr.s_addr = htonl((127 << 24) | 1);
        ctrl->dest.sin_port = htons(WPA_CTRL_IFACE_PORT);
        if (connect(ctrl->s, (struct sockaddr *) &ctrl->dest,
                    sizeof(ctrl->dest)) < 0) {
                perror("connect");
                close(ctrl->s);
                os_free(ctrl);
                return NULL;
        }

        len = sizeof(buf) - 1;
        if (wpa_ctrl_request(ctrl, "GET_COOKIE", 10, buf, &len, NULL) == 0) {
                buf[len] = '\0';
                ctrl->cookie = os_strdup(buf);
        }

        return ctrl;
}


void wpa_ctrl_close(struct wpa_ctrl *ctrl)
{
        close(ctrl->s);
        os_free(ctrl->cookie);
        os_free(ctrl);
}

#endif /* CONFIG_CTRL_IFACE_UDP */


#ifdef CTRL_IFACE_SOCKET
int wpa_ctrl_request(struct wpa_ctrl *ctrl, const char *cmd, size_t cmd_len,
                     char *reply, size_t *reply_len,
                     void (*msg_cb)(char *msg, size_t len))
{
        struct timeval tv;
        int res;
        fd_set rfds;
        const char *_cmd;
        char *cmd_buf = NULL;
        size_t _cmd_len;

#ifdef CONFIG_CTRL_IFACE_UDP
        if (ctrl->cookie) {
                char *pos;
                _cmd_len = os_strlen(ctrl->cookie) + 1 + cmd_len;
                cmd_buf = os_malloc(_cmd_len);
                if (cmd_buf == NULL)
                        return -1;
                _cmd = cmd_buf;
                pos = cmd_buf;
                os_strlcpy(pos, ctrl->cookie, _cmd_len);
                pos += os_strlen(ctrl->cookie);
                *pos++ = ' ';
                os_memcpy(pos, cmd, cmd_len);
        } else
#endif /* CONFIG_CTRL_IFACE_UDP */
        {
                _cmd = cmd;
                _cmd_len = cmd_len;
        }

        if (send(ctrl->s, _cmd, _cmd_len, 0) < 0) {
                os_free(cmd_buf);
                return -1;
        }
        os_free(cmd_buf);

        for (;;) {
                tv.tv_sec = 2;
                tv.tv_usec = 0;
                FD_ZERO(&rfds);
                FD_SET(ctrl->s, &rfds);
                res = select(ctrl->s + 1, &rfds, NULL, NULL, &tv);
                if (FD_ISSET(ctrl->s, &rfds)) {
                        res = recv(ctrl->s, reply, *reply_len, 0);
                        if (res < 0)
                                return res;
                        if (res > 0 && reply[0] == '<') {
                                /* This is an unsolicited message from
                                 * wpa_supplicant, not the reply to the
                                 * request. Use msg_cb to report this to the
                                 * caller. */
                                if (msg_cb) {
                                        /* Make sure the message is nul
                                         * terminated. */
                                        if ((size_t) res == *reply_len)
                                                res = (*reply_len) - 1;
                                        reply[res] = '\0';
                                        msg_cb(reply, res);
                                }
                                continue;
                        }
                        *reply_len = res;
                        break;
                } else {
                        return -2;
                }
        }
        return 0;
}
#endif /* CTRL_IFACE_SOCKET */


static int wpa_ctrl_attach_helper(struct wpa_ctrl *ctrl, int attach)
{
        char buf[10];
        int ret;
        size_t len = 10;

        ret = wpa_ctrl_request(ctrl, attach ? "ATTACH" : "DETACH", 6,
                               buf, &len, NULL);
        if (ret < 0)
                return ret;
        if (len == 3 && os_memcmp(buf, "OK\n", 3) == 0)
                return 0;
        return -1;
}


int wpa_ctrl_attach(struct wpa_ctrl *ctrl)
{
        return wpa_ctrl_attach_helper(ctrl, 1);
}


int wpa_ctrl_detach(struct wpa_ctrl *ctrl)
{
        return wpa_ctrl_attach_helper(ctrl, 0);
}


#ifdef CTRL_IFACE_SOCKET

int wpa_ctrl_recv(struct wpa_ctrl *ctrl, char *reply, size_t *reply_len)
{
        int res;

        res = recv(ctrl->s, reply, *reply_len, 0);
        if (res < 0)
                return res;
        *reply_len = res;
        return 0;
}


int wpa_ctrl_pending(struct wpa_ctrl *ctrl)
{
        struct timeval tv;
        fd_set rfds;
        tv.tv_sec = 0;
        tv.tv_usec = 0;
        FD_ZERO(&rfds);
        FD_SET(ctrl->s, &rfds);
        select(ctrl->s + 1, &rfds, NULL, NULL, &tv);
        return FD_ISSET(ctrl->s, &rfds);
}


int wpa_ctrl_get_fd(struct wpa_ctrl *ctrl)
{
        return ctrl->s;
}

#endif /* CTRL_IFACE_SOCKET */


#ifdef CONFIG_CTRL_IFACE_NAMED_PIPE

#ifndef WPA_SUPPLICANT_NAMED_PIPE
#define WPA_SUPPLICANT_NAMED_PIPE "WpaSupplicant"
#endif
#define NAMED_PIPE_PREFIX TEXT("\\\\.\\pipe\\") TEXT(WPA_SUPPLICANT_NAMED_PIPE)

struct wpa_ctrl * wpa_ctrl_open(const char *ctrl_path)
{
        struct wpa_ctrl *ctrl;
        DWORD mode;
        TCHAR name[256];
        int i, ret;

        ctrl = os_malloc(sizeof(*ctrl));
        if (ctrl == NULL)
                return NULL;
        os_memset(ctrl, 0, sizeof(*ctrl));

#ifdef UNICODE
        if (ctrl_path == NULL)
                ret = _snwprintf(name, 256, NAMED_PIPE_PREFIX);
        else
                ret = _snwprintf(name, 256, NAMED_PIPE_PREFIX TEXT("-%S"),
                                 ctrl_path);
#else /* UNICODE */
        if (ctrl_path == NULL)
                ret = os_snprintf(name, 256, NAMED_PIPE_PREFIX);
        else
                ret = os_snprintf(name, 256, NAMED_PIPE_PREFIX "-%s",
                                  ctrl_path);
#endif /* UNICODE */
        if (ret < 0 || ret >= 256) {
                os_free(ctrl);
                return NULL;
        }

        for (i = 0; i < 10; i++) {
                ctrl->pipe = CreateFile(name, GENERIC_READ | GENERIC_WRITE, 0,
                                        NULL, OPEN_EXISTING, 0, NULL);
                /*
                 * Current named pipe server side in wpa_supplicant is
                 * re-opening the pipe for new clients only after the previous
                 * one is taken into use. This leaves a small window for race
                 * conditions when two connections are being opened at almost
                 * the same time. Retry if that was the case.
                 */
                if (ctrl->pipe != INVALID_HANDLE_VALUE ||
                    GetLastError() != ERROR_PIPE_BUSY)
                        break;
                WaitNamedPipe(name, 1000);
        }
        if (ctrl->pipe == INVALID_HANDLE_VALUE) {
                os_free(ctrl);
                return NULL;
        }

        mode = PIPE_READMODE_MESSAGE;
        if (!SetNamedPipeHandleState(ctrl->pipe, &mode, NULL, NULL)) {
                CloseHandle(ctrl->pipe);
                os_free(ctrl);
                return NULL;
        }

        return ctrl;
}


void wpa_ctrl_close(struct wpa_ctrl *ctrl)
{
        CloseHandle(ctrl->pipe);
        os_free(ctrl);
}


int wpa_ctrl_request(struct wpa_ctrl *ctrl, const char *cmd, size_t cmd_len,
                     char *reply, size_t *reply_len,
                     void (*msg_cb)(char *msg, size_t len))
{
        DWORD written;
        DWORD readlen = *reply_len;

        if (!WriteFile(ctrl->pipe, cmd, cmd_len, &written, NULL))
                return -1;

        if (!ReadFile(ctrl->pipe, reply, *reply_len, &readlen, NULL))
                return -1;
        *reply_len = readlen;

        return 0;
}


int wpa_ctrl_recv(struct wpa_ctrl *ctrl, char *reply, size_t *reply_len)
{
        DWORD len = *reply_len;
        if (!ReadFile(ctrl->pipe, reply, *reply_len, &len, NULL))
                return -1;
        *reply_len = len;
        return 0;
}


int wpa_ctrl_pending(struct wpa_ctrl *ctrl)
{
        DWORD left;

        if (!PeekNamedPipe(ctrl->pipe, NULL, 0, NULL, &left, NULL))
                return -1;
        return left ? 1 : 0;
}


int wpa_ctrl_get_fd(struct wpa_ctrl *ctrl)
{
        return -1;
}

#endif /* CONFIG_CTRL_IFACE_NAMED_PIPE */

#endif /* CONFIG_CTRL_IFACE */