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/*
* libkarma/ssdp.c
*
* Copyright (c) Nicolas Justin+Gregrory Kokanosky 2004
* (c) Frank Zschockelt <libkarma@freakysoft.de> 2004
*
* You may distribute and modify this program under the terms of
* the GNU GPL, version 2 or later.
*
*/
/*
* This file is rudimentary implementation of the
* Simple Service Discovery Protocol/1.0, also known
* as Universal Plug'n'Play. Ths implementation is based
* on the draft v1.03 which can be found at:
* http://www.upnp.org/download/draft_cai_ssdp_v1_03.txt
*
* This feature is enabled by default on the Karma.
*/
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/socket.h>
#ifdef __NetBSD__
#include <netinet/in.h>
#endif
#include <netdb.h>
#include "lkarma.h"
#include "ssdp.h"
static int get_host_from_ssdp(char *buffer, char **hostname, uint16_t * port);
/* Parse the URL found at the "LOCATION:" entry of
* the SSDP reply in 'buffer'. 'hostname' and 'port'
* allocated, the caller is responsible to free them.
* 'hostname' is guaranteed to be null terminated.
* Return 0 on success, -1 otherwise.
*/
static int get_host_from_ssdp(char *buffer, char **hostname, uint16_t * port)
{
char *pos1, *pos2;
char tmp;
if((pos1 = strstr(buffer, "LOCATION:")) == NULL) {
return -1;
}
/* Find http:// */
if((pos1 = index(pos1, '/')) == NULL)
return -1;
pos1 += 2; /* jump to one char after http:// */
/* search the ':' in "hostname:4444" */
if((pos2 = index(pos1, ':')) == NULL)
return -1;
tmp = *pos2;
*pos2 = '\0';
/*copy the hostname */
if((*hostname = strdup(pos1)) == NULL)
return -1;
*pos2 = tmp;
/* Copy the port number */
/* Set pos2 to the end of the line */
pos1 = pos2 + 1;
if((pos2 = index(pos1, '\r')) == NULL)
return -1;
tmp = *pos2;
*pos2 = '\0';
*port = atoi(pos1);
*pos2 = tmp;
return 0;
}
/* Call this function if you want automatic discovery
* of a Karma on your network. A SSDP:discover is sent
* to the multicast address 239.255.255.250:1900, if
* a response is received, hostname and port are set
* respectivly to the Karma address (may be a hostname
* or an IP address), and the port wich listen to the
* Pearl protocol.
* Return 0 if succeed, or -1 on error.
*/
int lk_ssdp_discover(char **host, uint16_t * port)
{
int sock;
size_t ret;
unsigned int socklen;
struct sockaddr_in sockname;
struct sockaddr clientsock;
struct hostent *hostname;
char data[] =
"M-SEARCH * HTTP/1.1\r\n"
"Host: 239.255.255.250:1900\r\n"
"Man: \"ssdp:discover\"\r\n"
"ST: urn:empeg-com:protocol2\r\n" "MX: 3\r\n" "\r\n";
char buffer[RESPONSE_BUFFER_LEN];
unsigned int len = RESPONSE_BUFFER_LEN;
fd_set fds;
struct timeval timeout;
hostname = gethostbyname(SSDP_MULTICAST);
hostname->h_addrtype = AF_INET;
if((sock = socket(PF_INET, SOCK_DGRAM, 0)) == -1) {
lk_errors_set(E_SOCKET); /*err: socket() failed */
return -1;
}
memset((char *)&sockname, 0, sizeof(struct sockaddr_in));
sockname.sin_family = AF_INET;
sockname.sin_port = htons(SSDP_PORT);
sockname.sin_addr.s_addr = *((unsigned long *)(hostname->h_addr_list[0]));
ret = sendto(sock, data, strlen(data), 0, (struct sockaddr *)&sockname,
sizeof(struct sockaddr_in));
if(ret != strlen(data)) {
lk_errors_set(E_SENDTO); /*err: sendto() failed */
return -1;
}
/* Get response */
FD_ZERO(&fds);
FD_SET(sock, &fds);
timeout.tv_sec = 3;
timeout.tv_usec = 0;
if(select(sock + 1, &fds, NULL, NULL, &timeout) < 0) {
lk_errors_set(E_SELECT);
return -1;
}
if(FD_ISSET(sock, &fds)) {
socklen = sizeof(clientsock);
if((len = recvfrom(sock, buffer, len, MSG_PEEK,
&clientsock, &socklen)) == (size_t) - 1) {
lk_errors_set(E_RECVFROM); /*err: recvfrom() failed */
return -1;
}
buffer[len-1] = '\0';
close(sock);
/* Check the HTTP response code */
if(strncmp(buffer, "HTTP/1.1 200 OK", 12) != 0) {
lk_errors_set(E_SSDPPARSE);/*err: ssdp parsing failed */
return -1;
}
if(get_host_from_ssdp(buffer, host, port) == -1) {
lk_errors_set(E_SSDPPARSE);/*err: ssdp parsing failed */
return -1;
}
return 0;
} else {
lk_errors_set(E_NOSSDP); /*err: no ssdp answer */
return -1;
}
}
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