diff options
| -rw-r--r-- | mactelnet.c | 63 | ||||
| -rw-r--r-- | protocol.c | 2 | ||||
| -rw-r--r-- | protocol.h | 7 |
3 files changed, 56 insertions, 16 deletions
diff --git a/mactelnet.c b/mactelnet.c index 7be1f2a..b393eb1 100644 --- a/mactelnet.c +++ b/mactelnet.c @@ -68,8 +68,8 @@ unsigned char mt_direction_fromserver = 0; unsigned int send_socket; -static int send_udp(struct mt_packet *packet) { - +static int send_udp(struct mt_packet *packet, int retransmit) { + int sent_bytes; if (broadcast_mode) { /* Init SendTo struct */ struct sockaddr_in socket_address; @@ -77,11 +77,46 @@ static int send_udp(struct mt_packet *packet) { socket_address.sin_port = htons(MT_MACTELNET_PORT); socket_address.sin_addr.s_addr = htonl(INADDR_BROADCAST); - return sendto(send_socket, packet->data, packet->size, 0, (struct sockaddr*)&socket_address, sizeof(socket_address)); + sent_bytes = sendto(send_socket, packet->data, packet->size, 0, (struct sockaddr*)&socket_address, sizeof(socket_address)); } else { - return send_custom_udp(sockfd, device_index, srcmac, dstmac, &sourceip, sourceport, &destip, MT_MACTELNET_PORT, packet->data, packet->size); + sent_bytes = send_custom_udp(sockfd, device_index, srcmac, dstmac, &sourceip, sourceport, &destip, MT_MACTELNET_PORT, packet->data, packet->size); } + /* + * Retransmit packet if no data is received within + * retransmit_intervals milliseconds. + * + * TODO: Only stop retransmitting if received packet is + * an ACK packet. + */ + if (retransmit) { + int i; + + for (i = 0; i < MAX_RETRANSMIT_INTERVALS; ++i) { + fd_set read_fds; + int reads; + struct timeval timeout; + int interval = retransmit_intervals[i] * 1000; + + /* Init select */ + FD_ZERO(&read_fds); + FD_SET(insockfd, &read_fds); + timeout.tv_sec = 0; + timeout.tv_usec = interval; + + /* Wait for data or timeout */ + reads = select(insockfd + 1, &read_fds, NULL, NULL, &timeout); + if (reads && FD_ISSET(insockfd, &read_fds)) { + return sent_bytes; + } + + send_udp(packet, 0); + } + + fprintf(stderr, "\nConnection timed out\n"); + exit(1); + } + return sent_bytes; } static void send_auth(char *username, char *password) { @@ -121,7 +156,7 @@ static void send_auth(char *username, char *password) { outcounter += plen; /* TODO: handle result */ - result = send_udp(&data); + result = send_udp(&data, 1); } static void sig_winch(int sig) { @@ -136,7 +171,7 @@ static void sig_winch(int sig) { plen += add_control_packet(&data, MT_CPTYPE_TERM_HEIGHT, &height, 2); outcounter += plen; - result = send_udp(&data); + result = send_udp(&data, 1); } /* reinstate signal handler */ @@ -161,7 +196,7 @@ static void handle_packet(unsigned char *data, int data_len) { /* Always transmit ACKNOWLEDGE packets in response to DATA packets */ init_packet(&odata, MT_PTYPE_ACK, srcmac, dstmac, sessionkey, pkthdr.counter + (data_len - MT_HEADER_LEN)); - result = send_udp(&odata); + result = send_udp(&odata, 0); /* Accept first packet, and all packets greater than incounter, and if counter has wrapped around. */ @@ -219,7 +254,7 @@ static void handle_packet(unsigned char *data, int data_len) { /* Acknowledge the disconnection by sending a END packet in return */ init_packet(&odata, MT_PTYPE_END, srcmac, dstmac, pkthdr.seskey, 0); - result = send_udp(&odata); + result = send_udp(&odata, 0); fprintf(stderr, "Connection closed.\n"); @@ -277,7 +312,7 @@ static int find_interface() { /* Send a SESSIONSTART message with the current device */ init_packet(&data, MT_PTYPE_SESSIONSTART, srcmac, dstmac, sessionkey, 0); - send_udp(&data); + send_udp(&data, 0); timeout.tv_sec = connect_timeout; timeout.tv_usec = 0; @@ -305,9 +340,7 @@ int main (int argc, char **argv) { struct mt_packet data; struct sockaddr_in si_me; unsigned char buff[1500]; - struct timeval timeout; int keepalive_counter = 0; - fd_set read_fds; unsigned char print_help = 0, have_username = 0, have_password = 0; int c; int optval = 1; @@ -490,10 +523,12 @@ int main (int argc, char **argv) { outcounter += add_control_packet(&data, MT_CPTYPE_BEGINAUTH, NULL, 0); /* TODO: handle result of send_udp */ - result = send_udp(&data); + result = send_udp(&data, 1); while (running) { + fd_set read_fds; int reads; + struct timeval timeout; /* Init select */ FD_ZERO(&read_fds); @@ -521,7 +556,7 @@ int main (int argc, char **argv) { init_packet(&data, MT_PTYPE_DATA, srcmac, dstmac, sessionkey, outcounter); add_control_packet(&data, MT_CPTYPE_PLAINDATA, &keydata, datalen); outcounter += datalen; - result = send_udp(&data); + result = send_udp(&data, 1); } /* Handle select() timeout */ } else { @@ -531,7 +566,7 @@ int main (int argc, char **argv) { struct mt_packet odata; int plen=0,result=0; plen = init_packet(&odata, MT_PTYPE_ACK, srcmac, dstmac, sessionkey, 0); - result = send_udp(&odata); + result = send_udp(&odata, 0); } } } @@ -30,7 +30,7 @@ unsigned char mt_mactelnet_cpmagic[4] = { 0x56, 0x34, 0x12, 0xff }; unsigned char mt_mactelnet_clienttype[2] = { 0x00, 0x15 }; - +int retransmit_intervals[MAX_RETRANSMIT_INTERVALS] = { 15, 20, 30, 50, 90, 170, 330, 660, 1000 }; int init_packet(struct mt_packet *packet, enum mt_ptype ptype, unsigned char *srcmac, unsigned char *dstmac, unsigned short sessionkey, unsigned int counter) { unsigned char *data = packet->data; @@ -92,11 +92,16 @@ extern int parse_control_packet(unsigned char *data, int data_len, struct mt_mac struct mt_mndp_packet *parse_mndp(const unsigned char *data, const int packet_len); int query_mndp(const char *identity, unsigned char *mac); +/* Initialized by protocol.c */ +#define MAX_RETRANSMIT_INTERVALS 9 +extern int retransmit_intervals[MAX_RETRANSMIT_INTERVALS]; + /* Control packet magic header */ extern unsigned char mt_mactelnet_cpmagic[4]; extern unsigned char mt_mactelnet_clienttype[2]; -/* Must be defined by application */ +/* Must be initialized by application */ extern unsigned char mt_direction_fromserver; + #endif |