diff options
| -rw-r--r-- | Makefile | 10 | ||||
| -rw-r--r-- | jawol.c | 243 |
2 files changed, 237 insertions, 16 deletions
@@ -1,2 +1,8 @@ -all: - gcc -D_GNU_SOURCE -std=c99 -Os -g -Wall -Wextra -pedantic -o jawol jawol.c +CC ?= gcc +CFLAGS := -D_GNU_SOURCE -std=c99 -Os -g -Wall -Wextra -pedantic $(CFLAGS) + +jawol: jawol.c + $(CC) -o $@ $^ $(CFLAGS) + +clean: + rm -f -- jawol @@ -38,6 +38,13 @@ static const char usage_msg[] = " --destination IPADDR\n" " -d IPADDR Destination (broadcast) IP address.\n" "\n" +"Options for listening for WOL packets:\n" +" --listen\n" +" -l Listen for incoming WOL packets and print their contents.\n" +" Pass twice to force listening for UDP and RAW packets and\n" +" bail out if this fails. Otherwise, continue as long as at\n" +" least one of the sockets could be bound successfully.\n" +"\n" "Common options:\n" " --verbose\n" " -v Verbose mode, print some additional information.\n" @@ -69,6 +76,8 @@ static const char usage_msg[] = #include <linux/if.h> #include <sys/ioctl.h> #include <getopt.h> +#include <poll.h> +#include <fcntl.h> #define PACKET_SIZE (200) #define CHECK_PACKET_SIZE(x) do { \ @@ -96,6 +105,12 @@ static int rawsocket(); static int udpsocket(); static int etherwake(int count, char **macs); static int wakeonlan(int count, char **maclist); +static int wolisten(bool force); +static int rawrecv(int sock); +static int udprecv(int sock); +static int find_wol(const char *addr, const char *buffer, size_t buflen, const char *type); +static void formatpw(const uint8_t *pw, int len, char *output, size_t outlen); +static void sock_nonblock(int sock); static void print_usage(const char *a0) { @@ -104,9 +119,9 @@ static void print_usage(const char *a0) int main(int argc, char **argv) { - int opt; + int opt, dolisten = 0; bool gotip = false, gotif = false; - static const char *optString = "bDi:p:vhd:"; + static const char *optString = "bDi:p:vhd:l"; static const struct option longOpts[] = { { "broadcast", no_argument, NULL, 'b' }, { "debug", no_argument, NULL, 'D' }, @@ -115,6 +130,7 @@ int main(int argc, char **argv) { "verbose", no_argument, NULL, 'v' }, { "help", no_argument, NULL, 'h' }, { "destination", required_argument, NULL, 'd' }, + { "listen", no_argument, NULL, 'l' }, { 0, 0, 0, 0 } }; // Conveinience: Support MAC addr with dashes @@ -134,9 +150,17 @@ int main(int argc, char **argv) case 'v': options.verbose = true; break; case 'h': print_usage( argv[0] ); return 0; case 'd': options.dest = get_ip( optarg ); gotip = true; break; + case 'l': dolisten++; break; case '?': parse_errors++; break; } } + if ( dolisten && ( gotip || gotif || optind < argc ) ) { + fprintf( stderr, "Cannot combine -l with any other options.\n" ); + return 1; + } + if ( dolisten ) { + return wolisten( dolisten > 1 ); + } if ( gotip && gotif ) { fprintf( stderr, "Cannot use -d and -b/-i at the same time.\n" ); parse_errors++; @@ -252,13 +276,13 @@ static int rawsocket() if (errno == EPERM) { fprintf(stderr, "This program must be run as root for raw mode to work.\n"); } else { - perror("socket"); + perror("RAW socket()"); } return -1; } /* This is necessary for broadcasts to work */ if ( setsockopt( s, SOL_SOCKET, SO_BROADCAST, (char *)&one, sizeof(one) ) == -1 ) { - perror( "setsockopt: SO_BROADCAST" ); + perror( "RAW setsockopt: SO_BROADCAST" ); return -1; } return s; @@ -271,11 +295,11 @@ int udpsocket() sock = socket( AF_INET, SOCK_DGRAM, IPPROTO_UDP ); if ( sock == -1 ) { - perror( "socket" ); + perror( "UDP socket()" ); return -1; } if ( setsockopt( sock, SOL_SOCKET, SO_BROADCAST, (char *) &optval, sizeof( optval ) ) == -1 ) { - perror( "setsockopt: SO_BROADCAST" ); + perror( "UDP setsockopt: SO_BROADCAST" ); return -1; } @@ -377,12 +401,20 @@ static void get_wol_pw(const char *optarg) fprintf(stderr, "The impossible happened.\n"); abort(); } - printf(" The Magic packet password is %2.2x %2.2x %2.2x %2.2x (%d).\n", - passwd[0], passwd[1], passwd[2], passwd[3], byte_cnt); options.wolpwlen = byte_cnt; for (i = 0; i < byte_cnt; i++) { + if ( passwd[i] > 255 ) { + fprintf( stderr, "Password has invalid value for byte %d: %u.\n", + i, passwd[i] ); + parse_errors++; + } options.wolpw[i] = passwd[i]; } + if ( options.verbose ) { + char pw[20]; + formatpw( (uint8_t*)options.wolpw + i, byte_cnt, pw, sizeof(pw) ); + printf("The Magic packet password is %s.\n", pw); + } } /** @@ -406,11 +438,10 @@ static int get_source_addr(int s, const char *ifname, unsigned char *output) memcpy(output, if_hwaddr.ifr_hwaddr.sa_data, 6); if ( options.verbose ) { - unsigned char *hwaddr = (unsigned char*)if_hwaddr.ifr_hwaddr.sa_data; - printf("The hardware address (SIOCGIFHWADDR) of %s is type %d " - "%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x.\n", ifname, - if_hwaddr.ifr_hwaddr.sa_family, hwaddr[0], hwaddr[1], - hwaddr[2], hwaddr[3], hwaddr[4], hwaddr[5]); + char mac[20]; + formatpw( (uint8_t*)if_hwaddr.ifr_hwaddr.sa_data, 6, mac, sizeof(mac) ); + printf("The hardware address (SIOCGIFHWADDR) of %s is type %d" + " (%s).\n", ifname, if_hwaddr.ifr_hwaddr.sa_family, mac); } return 0; } @@ -440,7 +471,7 @@ static int get_dest_addr(const char *hostid, struct ether_addr *dest_ether) } } else { fprintf(stderr, - "ether-wake: The Magic Packet host address must be " + "The Magic Packet host address must be " "specified as\n" " - a station address, 00:11:22:33:44:55, or\n" " - a station address, 00-11-22-33-44-55, or\n" @@ -460,3 +491,187 @@ static struct in_addr get_ip(const char *arg) return tmp; } +static int wolisten(bool force) +{ + // TODO: RAW + struct pollfd socks[2] = {{.events = POLLIN},{.events = POLLIN}}; + int num = 0; + // UDP setup + int su = udpsocket(); + if ( su == -1 ) { + if ( force ) + return 1; + } else { + struct sockaddr_in addr = { + .sin_family = AF_INET, + .sin_port = htons( 9 ), + .sin_addr = { INADDR_ANY }, + }; + socklen_t addrlen = sizeof(addr); + sock_nonblock( su ); + if ( bind( su, (struct sockaddr*)&addr, addrlen ) == -1 ) { + perror( "bind on UDP socket" ); + close( su ); + if ( force ) + return 2; + } else { + socks[num++].fd = su; + if ( options.verbose ) { + printf( "Listening for UDP WOL packets\n" ); + } + } + } + // RAW setup + int sr = rawsocket(); + if ( sr == -1 ) { + if ( force ) + return 1; + } else { + struct sockaddr_ll addr = { + .sll_protocol = htons( 0x0842 ), + .sll_family = AF_PACKET, + }; + socklen_t addrlen = sizeof(addr); + sock_nonblock( sr ); + if ( bind( sr, (struct sockaddr*)&addr, addrlen ) == -1 ) { + perror( "bind on RAW socket" ); + close( sr ); + if ( force ) + return 2; + } else { + socks[num++].fd = sr; + if ( options.verbose ) { + printf( "Listening for RAW WOL packets\n" ); + } + } + } + // Ready to go? + if ( num == 0 ) + return 1; + for ( ;; ) { + if ( poll( socks, num, -1 ) == -1 ) { + if ( errno == EINTR || errno == EAGAIN ) + continue; + perror( "poll" ); + break; + } + for ( int i = 0; i < num; ++i ) { + if ( socks[i].revents == 0 ) + continue; + if ( socks[i].fd == su ) { + udprecv( su ); + } else if ( socks[i].fd == sr ) { + rawrecv( sr ); + } else { + abort(); + } + } + } + close( su ); + return 1; +} + +static const uint8_t ETHER_HEADER_LEN = 6 + 6 + 2; // 2x MAC + type + +static int rawrecv(int sock) +{ + char buffer[PACKET_SIZE], addrstr[50]; + struct sockaddr_ll src = {0}; + socklen_t srclen = sizeof(src); + ssize_t ret = recvfrom( sock, buffer, sizeof(buffer), 0, (struct sockaddr*)&src, &srclen ); + if ( ret < 0 ) { + if ( errno == EINTR || errno == EAGAIN ) + return 0; + perror( "recvfrom for RAW socket" ); + return 1; + } + if ( ret < ETHER_HEADER_LEN ) { + printf( "Short raw packet received (%d bytes)\n", (int)ret ); + return 0; + } + formatpw( (uint8_t*)src.sll_addr, src.sll_halen, addrstr, sizeof(addrstr) ); + if ( options.debug ) { + printf( "Received RAW packet of size %d from %s!\n", (int)ret, addrstr ); + } + return find_wol( addrstr, buffer + ETHER_HEADER_LEN, (size_t)ret - ETHER_HEADER_LEN, "RAW" ); +} + +static int udprecv(int sock) +{ + char buffer[PACKET_SIZE], addrstr[50]; + struct sockaddr_in src = {0}; + socklen_t srclen = sizeof(src); + ssize_t ret = recvfrom( sock, buffer, sizeof(buffer), 0, (struct sockaddr*)&src, &srclen ); + if ( ret < 0 ) { + if ( errno == EINTR || errno == EAGAIN ) + return 0; + perror( "recvfrom for UDP socket" ); + return 1; + } + if ( inet_ntop( AF_INET, &src.sin_addr, addrstr, sizeof(addrstr) ) == NULL ) { + perror( "Cannot determine source address of received UDP packet" ); + return 0; + } + if ( options.debug ) { + printf( "Received UDP datagram of size %d from %s!\n", (int)ret, addrstr ); + } + return find_wol( addrstr, buffer, (size_t)ret, "UDP" ); +} + +static int find_wol(const char *addrstr, const char *buffer, size_t buflen, const char *type) +{ + const uint8_t *sync = (uint8_t*)memmem( buffer, buflen, "\xff\xff\xff\xff\xff\xff", 6 ); + if ( sync == NULL ) { + if ( options.debug ) { + printf( "... no sync bytes found\n" ); + } + return 0; + } + sync += 6; + const uint8_t *end = (uint8_t*)buffer + buflen; + const uint8_t *pos = sync; + int count = 0; + while ( count < 16 && pos + 6 <= end ) { + if ( memcmp( sync, pos, 6 ) != 0 ) + break; + pos += 6; + count++; + } + if ( count == 16 ) { + char passwd[20]; + char mac[20]; + formatpw( sync, 6, mac, sizeof(mac) ); + formatpw( pos, end - pos, passwd, sizeof(passwd) ); + printf( "MAGIC source=%s dest=%s type=%s passwd=%s\n", addrstr, mac, type, passwd ); + } else if ( options.verbose ) { + printf( "Sync bytes found, with %d repetitions of the following 6 bytes.\n", count ); + } + return 0; +} + +static void formatpw(const uint8_t *pw, int len, char *output, size_t outlen) +{ + if ( outlen <= 0 ) + return; + if ( len == 4 ) { + snprintf( output, outlen, "%u.%u.%u.%u", pw[0], pw[1], pw[2], pw[3] ); + } else if ( len == 6 ) { + snprintf( output, outlen, "%02x:%02x:%02x:%02x:%02x:%02x", pw[0], pw[1], pw[2], pw[3], pw[4], pw[5] ); + } else { + *output = '\0'; + } +} + +static void sock_nonblock(int sock) +{ + errno = 0; + int f = fcntl( sock, F_GETFL ); + if ( errno != 0 ) { + perror( "fcntl(F_GETFL)" ); + return; + } + if ( fcntl( sock, F_SETFL, f | O_NONBLOCK ) == -1 ) { + perror( "fcntl(F_SETFL, ... | O_NONBLOCK)" ); + } +} + |