/****************************************************************************\

* WIFI - wifi connector with automatic connection modes

* By: Jesse McClure, copyright 2012

* License: GPLv3

* USAGE: wifi [ auto | any | add | reconnect ]

\****************************************************************************/

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <ncurses.h>

#include <iwlib.h>

#include <netinet/in.h>

/* for wireless tools v30.pre-9 */

#ifndef PROC_NET_WIRELESS

#define PROC_NET_WIRELESS "/proc/net/wireless"

#endif /* PROC_NET_WIRELESS */

#define MAX(a,b) (a > b ? a : b)

#define True 1

#define False 0

#define TIMEOUT 10

#define THRESHOLD 10

#define MAX_LINE 255

#define DHCPLEN 24

#define MODE_AUTO 0x0001

#define MODE_ANY 0x0002

#define MODE_ADD 0x0010

#define MODE_WAIT 0x0100

#define MODE_RECONNECT 0x0200

#define MODE_SECURE 0x1000

#define MODE_VERBOSE 0x2000

#define MODE_HIDDEN 0x4000

static int draw_entry(wireless_scan *, int);

static int is_known(wireless_scan *);

static wireless_scan *get_best();

static int refresh_list();

static int remove_network(const char *);

static wireless_scan *show_menu();

static int spawn(const char *,const char *);

static int ws_connect(wireless_scan *);

static char ifname[IFNAMSIZ+1] = "wlan0";

static const char *config = "/etc/swifer.conf";

static const char *netpath = "/usr/share/swifer/";

static char *hook_preup = NULL, *hook_postup = NULL;

static int we_ver, skfd, mode;

static wireless_scan_head context;

static wireless_config cur;

static char cmd[MAX_LINE+1] = "";

static char *killall = "killall", *wpa_sup = "wpa_supplicant", *re = "re", *an = "an";

static char dhcp[DHCPLEN+1] = "dhcpcd";

static const char *noname = " <hidden>";

int draw_entry(wireless_scan *ws,int sel) {

char *name = ws->b.essid;

if (!strlen(name)) name = (char *) noname;

/* known and/or currently connected */

if (strncmp(cur.essid,name,IW_ESSID_MAX_SIZE)==0) attrset(COLOR_PAIR(3)|A_BOLD);

else if (ws->b.key_flags == 2048) attrset(COLOR_PAIR(1)|A_BOLD);

else attrset(COLOR_PAIR(2)|A_BOLD);

if (is_known(ws)) printw("=> ");

else printw(" > ");

/* ESSID & selection cursor */

if (sel) attrset(COLOR_PAIR(3)|A_BOLD|A_REVERSE);

else attrset(COLOR_PAIR(0));

printw(" %-*s ",IW_ESSID_MAX_SIZE+2,name);

/* Connection strength */

int perc = 100 * ws->stats.qual.qual / 70;

if (perc > 94) attrset(COLOR_PAIR(2)|A_BOLD);

else if (perc > 84) attrset(COLOR_PAIR(2));

else if (perc > 64) attrset(COLOR_PAIR(3)|A_BOLD);

else attrset(COLOR_PAIR(1)|A_BOLD);

printw("%3d%%\n",perc);

return 1;

}

int is_known(wireless_scan *ws) {

if (!strlen(ws->b.essid)) return False;

FILE *cfg = fopen(config,"r");

if (!cfg) return False;

char line[MAX_LINE+1];

while ( (fgets(line,MAX_LINE,cfg)) != NULL)

if (strncmp(line,"[NETWORKS]",10) == 0)

break;

while ( (fgets(line,MAX_LINE,cfg)) != NULL) {

line[strlen(line)-1] = '\0';

if (strcmp(line,ws->b.essid) == 0) {

fclose(cfg);

return True;

}

}

fclose(cfg);

return False;

}

wireless_scan *get_best() {

wireless_scan *best=NULL,*ws;

unsigned short int known, sec, qual;

for (ws = context.result; ws; ws = ws->next) {

if (strlen(ws->b.essid) == 0) continue;

known = is_known(ws);

sec = (ws->b.key_flags == 2048);

qual = ( best ? (ws->stats.qual.qual > best->stats.qual.qual) : True);

if ( (qual && known) || (qual && (mode&MODE_ANY) && !sec) )

best = ws;

}

return best;

}

int refresh_list() {

clear();

attrset(COLOR_PAIR(3)|A_BOLD);

printw("\n\n Getting wifi listing ...\n");

refresh();

iw_scan(skfd,ifname,we_ver,&context);

wireless_scan *ws;

int n;

for (ws = context.result, n=0; ws; ws = ws->next)

if ((mode & MODE_HIDDEN) || strlen(ws->b.essid)) n++;

clear();

return n-1;

}

int remove_network(const char *network) {

sprintf(cmd,"rm \"%s%s\" > /dev/null 2>&1",netpath,network);

system(cmd);

FILE *cfg;

FILE *tmp;

if ( !(cfg=fopen(config,"r")) ) exit(1);

if ( !(tmp=fopen("/tmp/swifer.tmp","w")) ) {

fclose(cfg); exit(1);

}

while ( fgets(cmd,MAX_LINE,cfg) != NULL ) {

if (strncmp(cmd,network,strlen(network)) != 0) {

fprintf(tmp,cmd);

}

}

fclose(cfg); fclose(tmp);

sprintf(cmd,"mv /tmp/swifer.tmp %s",config);

system(cmd);

exit(0);

}

wireless_scan *show_menu() {

/* Init ncurses */

initscr(); raw(); noecho(); curs_set(0);

start_color(); use_default_colors();

init_pair(1,1,-1); init_pair(2,2,-1); init_pair(3,3,-1);

init_pair(4,4,-1); init_pair(5,5,-1); init_pair(6,6,-1);

init_pair(7,7,-1);

/* Select entry */

wireless_scan *ws, *ss;

int running = True;

int c,i,sel = 0;

int n = refresh_list();

while (running) {

move(0,0);

attrset(COLOR_PAIR(4)|A_REVERSE|A_BOLD);

printw(" * %-*s %% \n",IW_ESSID_MAX_SIZE+2,"Network");

for (ws = context.result, i=0; ws; ws = ws->next)

if ((mode & MODE_HIDDEN) || strlen(ws->b.essid)) {

if (i == sel) ss = ws;

draw_entry(ws,((i++)==sel));

}

attrset(COLOR_PAIR(4)|A_REVERSE|A_BOLD);

printw(" %-*s \n",IW_ESSID_MAX_SIZE+8," ");

refresh();

c = getchar();

if (c == 'q') running = False;

else if (c == 13) break;

else if (c == 'r') n = refresh_list();

else if (c == 'j' || c == 66) sel++;

else if (c == 'k' || c == 65) sel--;

if (sel >= n) sel = n;

else if (sel < 0) sel = 0;

}

endwin();

if (!running) { /* "q" selected */

iw_sockets_close(skfd);

exit(0);

}

for (i = 0, ws = context.result; i != sel; ws = ws->next)

if ((mode & MODE_HIDDEN) || strlen(ws->b.essid)) i++;

/* End ncurses session & return result */

return ws;

}

int spawn(const char *proc,const char *netfile) {

if (fork() != 0) return 0;

const char *args[7];

args[0] = proc;

if (netfile) {

args[1] = "-B"; args[2] = "-i"; args[3] = ifname;

args[4] = "-c"; args[5] = netfile; args[6] = NULL;

}

else {

args[1] = ifname; args[2] = NULL;

}

setsid(); fclose(stderr); fclose(stdout);

execvp(args[0],(char * const *)args);

}

int ws_connect(wireless_scan *ws) {

char *netfile = NULL;

if (hook_preup) system(hook_preup);

if (mode & MODE_SECURE) {

netfile = (char *) calloc(strlen(netpath)+strlen(ws->b.essid)+2,

sizeof(char));

strcpy(netfile,netpath);

strcat(netfile,ws->b.essid);

}

if ( !is_known(ws) && (mode & MODE_SECURE)) { /* secure unknown network */

char psk[64];

fprintf(stdout,"Enter passkey for \"%s\"\n> ",ws->b.essid);

fflush(stdout);

scanf("%s",psk);

sprintf(cmd,"wpa_passphrase \"%s\" \"%s\" > \"%s\"",ws->b.essid,psk,netfile);

system(cmd);

}

if (mode & MODE_SECURE) { /* secure known/new */

spawn("wpa_supplicant",netfile);

}

else { /* unsecure network */

struct iwreq req;

req.u.essid.flags = 1;

req.u.essid.pointer = (caddr_t) ws->b.essid;

req.u.essid.length = strlen(ws->b.essid);

if (we_ver < 21) req.u.essid.length++;

iw_set_ext(skfd,ifname,SIOCSIWESSID,&req);

}

if (!is_known(ws) && (mode & MODE_ADD)) {

FILE *cfg;

if ( (cfg=fopen(config,"ax")) ) /* no config file, create new */

fprintf(cfg,"\n[NETWORKS]\n%s\n",ws->b.essid);

else if ( (cfg=fopen(config,"a")) ) /* normal append */

fprintf(cfg,"%s\n",ws->b.essid);

if (cfg) fclose(cfg);

}

else if (!is_known(ws) && (mode & MODE_SECURE)) {

sprintf(cmd,"rm \"%s\"",netfile);

system(cmd);

}

if (netfile) {

free(netfile);

netfile = NULL;

}

spawn(dhcp,netfile);

if (hook_postup) system(hook_postup);

}

int main(int argc, const char **argv) {

/* Check uid */

if (getuid() != 0) {

fprintf(stderr,"Swifer must be run as root.\n");

return 1;

}

/* Check config file for interface and dhcp */

FILE *cfg;

if ( (cfg=fopen(config,"r")) ) {

char *line = calloc(MAX_LINE+1,sizeof(char));

char *val = calloc(MAX_LINE+1,sizeof(char));

while (fgets(line,MAX_LINE,cfg) != NULL) {

if (line[0] == '#') continue;

if (sscanf(line,"INTERFACE = %s",val))

strncpy(ifname,val,IFNAMSIZ);

else if (sscanf(line,"DHCP = %s",val))

strncpy(dhcp,val,DHCPLEN);

else if (sscanf(line,"PRE_UP = %s",val))

hook_preup = strdup(val);

else if (sscanf(line,"POST_UP = %s",val))

hook_postup = strdup(val);

else if (strncmp(line,"[NETWORKS]",10)==0)

break;

}

free(line); free(val); fclose(cfg);

}

/* Get basic wifi info */

we_ver = iw_get_kernel_we_version();

skfd = iw_sockets_open();

iw_get_basic_config(skfd,ifname,&cur);

/* Bring up interface (eg "ip link set IFACE up") */

struct ifreq req;

int err;

strncpy(req.ifr_name,ifname,IFNAMSIZ);

if ( (err=ioctl(skfd,SIOCGIFFLAGS,&req)) ){

int loop = 0;

while ( (err=ioctl(skfd,SIOCGIFFLAGS,&req)) ) {

usleep(100000);

if (loop++ > 50) break;

}

if (err) {

close(skfd);

return 2;

}

}

req.ifr_flags |= IFF_UP;

if (ioctl(skfd,SIOCSIFFLAGS,&req)) {

close(skfd); return 3;

}

/* Processes command line arguments */

int i;

for (i = 1; i < argc; i++) {

if (strncmp(argv[i],"ad",2)==0) mode |= MODE_ADD;

else if (strncmp(argv[i],"au",2)==0) mode |= MODE_AUTO;

else if (strncmp(argv[i],"hi",2)==0) mode |= MODE_HIDDEN;

else if (strncmp(argv[i],"an",2)==0) mode |= (MODE_ANY | MODE_AUTO);

else if (strncmp(argv[i],"re",2)==0) mode |= (MODE_RECONNECT | MODE_AUTO);

else if (strncmp(argv[i],"ve",2)==0) mode |= MODE_VERBOSE;

else if (strncmp(argv[i],"wa",2)==0) mode |= MODE_WAIT;

else if (strncmp(argv[i],"de",2)==0) {

if (argc > i+1) remove_network(argv[i+1]);

}

else fprintf(stderr,"[%s] Ignoring unknown parameter: %s\n",

argv[0],argv[i]);

}

if ( (mode & MODE_VERBOSE) && (mode & MODE_AUTO) ) mode &= ~MODE_VERBOSE;

/* Scan and select network */

iw_scan(skfd,ifname,we_ver,&context);

wireless_scan *ws;

if (mode & MODE_AUTO) {

if (mode && MODE_WAIT) {

int loops;

/* keep trying for up to 5 minutes */

for (loops = 0; loops < 30 && !(ws=get_best()); ++loops)

sleep(TIMEOUT);

}

else ws = get_best();

}

else ws = show_menu();

const char *arg[4];

if (ws) { /* Stop any current processes then connect to "ws" */

arg[0] = killall; arg[1] = dhcp; arg[2] = NULL;

if (fork()==0) {

fclose(stdout); fclose(stderr);

execvp(arg[0],(char * const *) arg);

}

arg[1] = wpa_sup;

if (fork()==0) {

fclose(stdout); fclose(stderr);

execvp(arg[0],(char * const *) arg);

}

sleep(1);

if ( (mode & MODE_ADD) && is_known(ws) ) mode &= ~MODE_ADD;

if (ws->b.key_flags == 2048) mode |= MODE_SECURE;

mode_t pre = umask(S_IWGRP|S_IWOTH|S_IRGRP|S_IROTH);

ws_connect(ws);

umask(pre);

}

else if ( !(mode & MODE_RECONNECT) ) {

fprintf(stderr,"[swifer] no suitable networks found.\n");

return 5;

}

/* Keep alive to reconnect? */

iw_sockets_close(skfd);

if (mode & MODE_RECONNECT) {

if (fork() == 0) {

setsid();

int level = THRESHOLD + 1, ret;

char scanline[256];

snprintf(scanline,255,"%%*[^\n]\n%%*[^\n]\n%s: %%*d %%d.",ifname);

FILE *procw;

while (level > THRESHOLD) {

sleep(TIMEOUT);

procw = fopen(PROC_NET_WIRELESS,"r");

ret = fscanf(procw,scanline,&level);

fclose(procw);

if (ret != 1) level = 0;

}

arg[0] = argv[0]; arg[1] = re; arg[2] = an; arg[3] = NULL;

if ( !(mode & MODE_ANY)) arg[2] = NULL;

execvp(arg[0],(char * const *) arg);

}

}

if (hook_preup) free(hook_preup);

if (hook_postup) free(hook_postup);

return 0;

}