int daemon_updatefilter(pcap_t *fp, uint32 plen)
{
struct rpcap_header header; // keeps the answer to the updatefilter command
unsigned int nread;
if ( daemon_unpackapplyfilter(fp, &nread, &plen, fp->errbuf) )
goto error;
// Check if all the data has been read; if not, discard the data in excess
if (nread != plen)
{
if (sock_discard(fp->rmt_sockctrl, plen - nread, fakeerrbuf) )
{
nread= plen; // just to avoid to call discard again in the 'error' section
goto error;
}
}
// A response is needed, otherwise the other host does not know that everything went well
rpcap_createhdr( &header, RPCAP_MSG_UPDATEFILTER_REPLY, 0, 0);
if ( sock_send(fp->rmt_sockctrl, (char *) &header, sizeof (struct rpcap_header), fp->errbuf) )
goto error;
return 0;
error:
if (nread != plen)
sock_discard(fp->rmt_sockctrl, plen - nread, fakeerrbuf);
rpcap_senderror(fp->rmt_sockctrl, fp->errbuf, PCAP_ERR_UPDATEFILTER, fakeerrbuf);
return -1;
}
/*!
\brief Received the sampling parameters from remote host and it stores in the pcap_t structure.
*/
int daemon_setsampling(SOCKET sockctrl, struct rpcap_sampling *samp_param, int plen, char *errbuf)
{
struct rpcap_header header;
struct rpcap_sampling rpcap_samp;
int nread; // number of bytes of the payload read from the socket
if ( ( nread= sock_recv(sockctrl, (char *) &rpcap_samp, sizeof(struct rpcap_sampling),
SOCK_RECEIVEALL_YES, errbuf, PCAP_ERRBUF_SIZE)) == -1)
goto error;
// Save these settings in the pcap_t
samp_param->method= rpcap_samp.method;
samp_param->value= ntohl(rpcap_samp.value);
// A response is needed, otherwise the other host does not know that everything went well
rpcap_createhdr( &header, RPCAP_MSG_SETSAMPLING_REPLY, 0, 0);
if ( sock_send(sockctrl, (char *) &header, sizeof (struct rpcap_header), errbuf, PCAP_ERRBUF_SIZE) )
goto error;
if (nread != plen)
sock_discard(sockctrl, plen - nread, NULL, 0);
return 0;
error:
if (nread != plen)
sock_discard(sockctrl, plen - nread, NULL, 0);
rpcap_senderror(sockctrl, errbuf, PCAP_ERR_SETSAMPLING, NULL);
return -1;
}
/*!
\brief Main serving funtion
This function is the one which does the job. It is the main() of the child
thread, which is created as soon as a new connection is accepted.
\param ptr: a void pointer that keeps the reference of the 'pthread_chain'
value corrisponding to this thread. This variable is casted into a 'pthread_chain'
value in order to retrieve the socket we're currently using, the therad ID, and
some pointers to the previous and next elements into this struct.
\return None.
*/
void daemon_serviceloop( void *ptr )
{
char errbuf[PCAP_ERRBUF_SIZE + 1]; // keeps the error string, prior to be printed
char source[PCAP_BUF_SIZE]; // keeps the string that contains the interface to open
struct rpcap_header header; // RPCAP message general header
pcap_t *fp= NULL; // pcap_t main variable
struct daemon_slpars *pars; // parameters related to the present daemon loop
pthread_t threaddata= 0; // handle to the 'read from daemon and send to client' thread
unsigned int ifdrops, ifrecv, krnldrop, svrcapt; // needed to save the values of the statistics
struct rpcap_sampling samp_param; // in case sampling has been requested
// Structures needed for the select() call
fd_set rfds; // set of socket descriptors we have to check
struct timeval tv; // maximum time the select() can block waiting for data
int retval; // select() return value
pars= (struct daemon_slpars *) ptr;
*errbuf= 0; // Initialize errbuf
// If we're in active mode, this is not a separate thread
if (! pars->isactive)
{
// Modify thread params so that it can be killed at any time
if (pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL) )
goto end;
if (pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL) )
goto end;
}
auth_again:
// If we're in active mode, we have to check for the initial timeout
if (!pars->isactive)
{
FD_ZERO(&rfds);
// We do not have to block here
tv.tv_sec = RPCAP_TIMEOUT_INIT;
tv.tv_usec = 0;
FD_SET(pars->sockctrl, &rfds);
retval = select(pars->sockctrl + 1, &rfds, NULL, NULL, &tv);
if (retval == -1)
{
sock_geterror("select(): ", errbuf, PCAP_ERRBUF_SIZE);
rpcap_senderror(pars->sockctrl, errbuf, PCAP_ERR_NETW, NULL);
goto end;
}
// The timeout has expired
// So, this was a fake connection. Drop it down
if (retval == 0)
{
rpcap_senderror(pars->sockctrl, "The RPCAP initial timeout has expired", PCAP_ERR_INITTIMEOUT, NULL);
goto end;
}
}
retval= daemon_checkauth(pars->sockctrl, pars->nullAuthAllowed, errbuf);
if (retval)
{
// the other user requested to close the connection
// It can be also the case of 'active mode', in which this host is not
// allowed to connect to the other peer; in that case, it drops down the connection
if (retval == -3)
goto end;
// It can be an authentication failure or an unrecoverable error
rpcap_senderror(pars->sockctrl, errbuf, PCAP_ERR_AUTH, NULL);
// authentication error
if (retval == -2)
{
// suspend for 1 sec
// WARNING: this day is inserted only in this point; if the user drops down the connection
// and it connects again, this suspension time does not have any effects.
pthread_suspend(RPCAP_SUSPEND_WRONGAUTH*1000);
goto auth_again;
}
// Unrecoverable error
if (retval == -1)
goto end;
}
while (1)
{
int retval;
errbuf[0]= 0; // clear errbuf
// Avoid zombies connections; check if the connection is opens but no commands are performed
// from more than RPCAP_TIMEOUT_RUNTIME
// Conditions:
// - I have to be in normal mode (no active mode)
// - if the device is open, I don't have to be in the middle of a capture (fp->rmt_sockdata)
// - if the device is closed, I have always to check if a new command arrives
//
// Be carefully: the capture can have been started, but an error occurred (so fp != NULL, but
// rmt_sockdata is 0
if ( (!pars->isactive) && ( (fp == NULL) || ( (fp != NULL) && (fp->rmt_sockdata == 0) ) ))
{
// Check for the initial timeout
FD_ZERO(&rfds);
// We do not have to block here
tv.tv_sec = RPCAP_TIMEOUT_RUNTIME;
tv.tv_usec = 0;
FD_SET(pars->sockctrl, &rfds);
retval = select(pars->sockctrl + 1, &rfds, NULL, NULL, &tv);
if (retval == -1)
{
sock_geterror("select(): ", errbuf, PCAP_ERRBUF_SIZE);
rpcap_senderror(pars->sockctrl, errbuf, PCAP_ERR_NETW, NULL);
goto end;
}
// The timeout has expired
// So, this was a fake connection. Drop it down
if (retval == 0)
{
SOCK_ASSERT("The RPCAP runtime timeout has expired", 1);
rpcap_senderror(pars->sockctrl, "The RPCAP runtime timeout has expired", PCAP_ERR_RUNTIMETIMEOUT, NULL);
goto end;
}
}
if (sock_recv(pars->sockctrl, (char *) &header, sizeof(struct rpcap_header), SOCK_RECEIVEALL_YES, errbuf, PCAP_ERRBUF_SIZE) == -1)
goto end;
// Checks if the message is correct
// In case it is wrong, it discard the data
retval= rpcap_checkmsg(errbuf, pars->sockctrl, &header,
RPCAP_MSG_FINDALLIF_REQ,
RPCAP_MSG_OPEN_REQ,
RPCAP_MSG_STARTCAP_REQ,
RPCAP_MSG_UPDATEFILTER_REQ,
RPCAP_MSG_STATS_REQ,
RPCAP_MSG_ENDCAP_REQ,
RPCAP_MSG_SETSAMPLING_REQ,
RPCAP_MSG_CLOSE,
RPCAP_MSG_ERROR,
0);
switch (retval)
{
case -3: // Unrecoverable network error
goto end; // Do nothing; just exit from findalldevs; the error code is already into the errbuf
case -2: // The other endpoint send a message that is not allowed here
{
rpcap_senderror(pars->sockctrl, "The RPCAP daemon received a message that is not valid", PCAP_ERR_WRONGMSG, errbuf);
}
case -1: // The other endpoint has a version number that is not compatible with our
{
rpcap_senderror(pars->sockctrl, "RPCAP version number mismatch", PCAP_ERR_WRONGVER, errbuf);
}
break;
case RPCAP_MSG_FINDALLIF_REQ:
{
// Checks that the header does not contain other data; if so, discard it
if (ntohl(header.plen))
sock_discard(pars->sockctrl, ntohl(header.plen), errbuf, PCAP_ERRBUF_SIZE);
if (daemon_findalldevs(pars->sockctrl, errbuf) )
SOCK_ASSERT(errbuf, 1);
break;
};
case RPCAP_MSG_OPEN_REQ:
{
retval= daemon_opensource(pars->sockctrl, source, sizeof(source), ntohl(header.plen), errbuf);
if (retval == -1)
SOCK_ASSERT(errbuf, 1);
break;
};
case RPCAP_MSG_SETSAMPLING_REQ:
{
retval= daemon_setsampling(pars->sockctrl, &samp_param, ntohl(header.plen), errbuf);
if (retval == -1)
SOCK_ASSERT(errbuf, 1);
break;
};
case RPCAP_MSG_STARTCAP_REQ:
{
fp= daemon_startcapture(pars->sockctrl, &threaddata, source, pars->isactive, &samp_param, ntohl(header.plen), errbuf);
if (fp == NULL)
SOCK_ASSERT(errbuf, 1);
break;
};
case RPCAP_MSG_UPDATEFILTER_REQ:
{
if (fp)
{
if (daemon_updatefilter(fp, ntohl(header.plen)) )
SOCK_ASSERT(fp->errbuf, 1);
}
else
{
rpcap_senderror(pars->sockctrl, "Device not opened. Cannot update filter", PCAP_ERR_UPDATEFILTER, errbuf);
}
break;
};
case RPCAP_MSG_STATS_REQ:
{
// Checks that the header does not contain other data; if so, discard it
if (ntohl(header.plen))
sock_discard(pars->sockctrl, ntohl(header.plen), errbuf, PCAP_ERRBUF_SIZE);
if (fp)
{
if (daemon_getstats(fp) )
SOCK_ASSERT(fp->errbuf, 1);
}
else
{
SOCK_ASSERT("GetStats: this call should't be allowed here", 1);
if (daemon_getstatsnopcap(pars->sockctrl, ifdrops, ifrecv, krnldrop, svrcapt, errbuf) )
SOCK_ASSERT(errbuf, 1);
// we have to keep compatibility with old applications, which ask for statistics
// also when the capture has already stopped
// rpcap_senderror(pars->sockctrl, "Device not opened. Cannot get statistics", PCAP_ERR_GETSTATS, errbuf);
}
break;
};
case RPCAP_MSG_ENDCAP_REQ: // The other endpoint close the current capture session
{
if (fp)
{
struct pcap_stat stats;
// Save statistics (we can need them in the future)
if (pcap_stats(fp, &stats) )
{
ifdrops= stats.ps_ifdrop;
ifrecv= stats.ps_recv;
krnldrop= stats.ps_drop;
svrcapt= fp->md.TotCapt;
}
else
ifdrops= ifrecv= krnldrop= svrcapt= 0;
if ( daemon_endcapture(fp, &threaddata, errbuf) )
SOCK_ASSERT(errbuf, 1);
fp= NULL;
}
else
{
rpcap_senderror(pars->sockctrl, "Device not opened. Cannot close the capture", PCAP_ERR_ENDCAPTURE, errbuf);
}
break;
};
case RPCAP_MSG_CLOSE: // The other endpoint close the pcap session
{
// signal to the main that the user closed the control connection
// This is used only in case of active mode
pars->activeclose= 1;
SOCK_ASSERT("The other end system asked to close the connection.", 1);
goto end;
break;
};
case RPCAP_MSG_ERROR: // The other endpoint reported an error
{
// Do nothing; just exit; the error code is already into the errbuf
SOCK_ASSERT(errbuf, 1);
break;
};
default:
{
SOCK_ASSERT("Internal error.", 1);
break;
};
}
}
end:
// The child thread is about to end
// perform pcap_t cleanup, in case it has not been done
if (fp)
{
if (threaddata)
{
pthread_cancel(threaddata);
threaddata= 0;
}
if (fp->rmt_sockdata)
{
sock_close(fp->rmt_sockdata, NULL, 0);
fp->rmt_sockdata= 0;
}
pcap_close(fp);
fp= NULL;
}
// Print message and exit
SOCK_ASSERT("I'm exiting from the child loop", 1);
SOCK_ASSERT(errbuf, 1);
if (!pars->isactive)
{
if (pars->sockctrl)
sock_close(pars->sockctrl, NULL, 0);
free(pars);
#ifdef WIN32
pthread_exit(0);
#endif
}
}
/*
\param plen: the length of the current message (needed in order to be able
to discard excess data in the message, if present)
*/
pcap_t *daemon_startcapture(SOCKET sockctrl, pthread_t *threaddata, char *source, int active, struct rpcap_sampling *samp_param, uint32 plen, char *errbuf)
{
char portdata[PCAP_BUF_SIZE]; // temp variable needed to derive the data port
char peerhost[PCAP_BUF_SIZE]; // temp variable needed to derive the host name of our peer
pcap_t *fp= NULL; // pcap_t main variable
unsigned int nread; // number of bytes of the payload read from the socket
char sendbuf[RPCAP_NETBUF_SIZE]; // temporary buffer in which data to be sent is buffered
int sendbufidx= 0; // index which keeps the number of bytes currently buffered
// socket-related variables
SOCKET sockdata= 0; // socket descriptor of the data connection
struct addrinfo hints; // temp, needed to open a socket connection
struct addrinfo *addrinfo; // temp, needed to open a socket connection
struct sockaddr_storage saddr; // temp, needed to retrieve the network data port chosen on the local machine
socklen_t saddrlen; // temp, needed to retrieve the network data port chosen on the local machine
pthread_attr_t detachedAttribute; // temp, needed to set the created thread as detached
// RPCAP-related variables
struct rpcap_startcapreq startcapreq; // start capture request message
struct rpcap_startcapreply *startcapreply; // start capture reply message
int serveropen_dp; // keeps who is going to open the data connection
addrinfo= NULL;
if ( (nread= sock_recv(sockctrl, (char *) &startcapreq, sizeof(struct rpcap_startcapreq), SOCK_RECEIVEALL_YES, errbuf, PCAP_ERRBUF_SIZE)) == -1)
return NULL;
startcapreq.flags= ntohs(startcapreq.flags);
// Open the selected device
if ( (fp= pcap_open(source,
ntohl(startcapreq.snaplen),
(startcapreq.flags & RPCAP_STARTCAPREQ_FLAG_PROMISC) ? PCAP_OPENFLAG_PROMISCUOUS : 0 /* local device, other flags not needed */,
ntohl(startcapreq.read_timeout),
NULL /* local device, so no auth */,
errbuf)) == NULL)
{
rpcap_senderror(sockctrl, errbuf, PCAP_ERR_OPEN, NULL);
return NULL;
}
// Apply sampling parameters
fp->rmt_samp.method= samp_param->method;
fp->rmt_samp.value= samp_param->value;
/*
We're in active mode if:
- we're using TCP, and the user wants us to be in active mode
- we're using UDP
*/
serveropen_dp= (startcapreq.flags & RPCAP_STARTCAPREQ_FLAG_SERVEROPEN) || (startcapreq.flags & RPCAP_STARTCAPREQ_FLAG_DGRAM) || active;
/*
Gets the sockaddr structure referred to the other peer in the ctrl connection
We need that because:
- if we're in passive mode, we need to know the address family we want to use
(the same used for the ctrl socket)
- if we're in active mode, we need to know the network address of the other host
we want to connect to
*/
saddrlen = sizeof(struct sockaddr_storage);
if (getpeername(sockctrl, (struct sockaddr *) &saddr, &saddrlen) == -1)
{
sock_geterror("getpeername(): ", errbuf, PCAP_ERRBUF_SIZE);
goto error;
}
memset(&hints, 0, sizeof(struct addrinfo) );
hints.ai_socktype = (startcapreq.flags & RPCAP_STARTCAPREQ_FLAG_DGRAM) ? SOCK_DGRAM : SOCK_STREAM;
hints.ai_family = saddr.ss_family;
// Now we have to create a new socket to send packets
if (serveropen_dp) // Data connection is opened by the server toward the client
{
sprintf(portdata, "%d", ntohs(startcapreq.portdata) );
// Get the name of the other peer (needed to connect to that specific network address)
if (getnameinfo( (struct sockaddr *) &saddr, saddrlen, peerhost,
sizeof(peerhost), NULL, 0, NI_NUMERICHOST) )
{
sock_geterror("getnameinfo(): ", errbuf, PCAP_ERRBUF_SIZE);
goto error;
}
if (sock_initaddress(peerhost, portdata, &hints, &addrinfo, errbuf, PCAP_ERRBUF_SIZE) == -1)
goto error;
if ( (sockdata= sock_open(addrinfo, SOCKOPEN_CLIENT, 0, errbuf, PCAP_ERRBUF_SIZE)) == -1)
goto error;
}
else // Data connection is opened by the client toward the server
{
hints.ai_flags = AI_PASSIVE;
// Let's the server socket pick up a free network port for us
if (sock_initaddress(NULL, "0", &hints, &addrinfo, errbuf, PCAP_ERRBUF_SIZE) == -1)
goto error;
if ( (sockdata= sock_open(addrinfo, SOCKOPEN_SERVER, 1 /* max 1 connection in queue */, errbuf, PCAP_ERRBUF_SIZE)) == -1)
goto error;
// get the complete sockaddr structure used in the data connection
saddrlen = sizeof(struct sockaddr_storage);
if (getsockname(sockdata, (struct sockaddr *) &saddr, &saddrlen) == -1)
{
sock_geterror("getsockname(): ", errbuf, PCAP_ERRBUF_SIZE);
goto error;
}
// Get the local port the system picked up
if (getnameinfo( (struct sockaddr *) &saddr, saddrlen, NULL,
0, portdata, sizeof(portdata), NI_NUMERICSERV) )
{
sock_geterror("getnameinfo(): ", errbuf, PCAP_ERRBUF_SIZE);
goto error;
}
}
// addrinfo is no longer used
freeaddrinfo(addrinfo);
addrinfo= NULL;
// save the socket ID for the next calls
fp->rmt_sockctrl= sockctrl; // Needed to send an error on the ctrl connection
// Now I can set the filter
if ( daemon_unpackapplyfilter(fp, &nread, &plen, errbuf) )
goto error;
// Now, I can send a RPCAP start capture reply message
if ( sock_bufferize(NULL, sizeof(struct rpcap_header), NULL, &sendbufidx,
RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, errbuf, PCAP_ERRBUF_SIZE) == -1)
goto error;
rpcap_createhdr( (struct rpcap_header *) sendbuf, RPCAP_MSG_STARTCAP_REPLY, 0, sizeof(struct rpcap_startcapreply) );
startcapreply= (struct rpcap_startcapreply *) &sendbuf[sendbufidx];
if ( sock_bufferize(NULL, sizeof(struct rpcap_startcapreply), NULL,
&sendbufidx, RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, errbuf, PCAP_ERRBUF_SIZE) == -1)
goto error;
memset(startcapreply, 0, sizeof(struct rpcap_startcapreply) );
startcapreply->bufsize= htonl(fp->bufsize);
if (!serveropen_dp)
{
unsigned short port = (unsigned short)strtoul(portdata,NULL,10);
startcapreply->portdata= htons(port);
}
if ( sock_send(sockctrl, sendbuf, sendbufidx, errbuf, PCAP_ERRBUF_SIZE) == -1)
goto error;
if (!serveropen_dp)
{
SOCKET socktemp; // We need another socket, since we're going to accept() a connection
// Connection creation
saddrlen = sizeof(struct sockaddr_storage);
socktemp= accept(sockdata, (struct sockaddr *) &saddr, &saddrlen);
if (socktemp == -1)
{
sock_geterror("accept(): ", errbuf, PCAP_ERRBUF_SIZE);
goto error;
}
// Now that I accepted the connection, the server socket is no longer needed
sock_close(sockdata, errbuf, PCAP_ERRBUF_SIZE);
sockdata= socktemp;
}
fp->rmt_sockdata= sockdata;
/* GV we need this to create the thread as detached. */
/* GV otherwise, the thread handle is not destroyed */
pthread_attr_init(&detachedAttribute);
pthread_attr_setdetachstate(&detachedAttribute, PTHREAD_CREATE_DETACHED);
// Now we have to create a new thread to receive packets
if ( pthread_create(threaddata, &detachedAttribute, (void *) daemon_thrdatamain, (void *) fp) )
{
snprintf(errbuf, PCAP_ERRBUF_SIZE, "Error creating the data thread");
pthread_attr_destroy(&detachedAttribute);
goto error;
}
pthread_attr_destroy(&detachedAttribute);
// Check if all the data has been read; if not, discard the data in excess
if (nread != plen)
sock_discard(sockctrl, plen - nread, NULL, 0);
return fp;
error:
rpcap_senderror(sockctrl, errbuf, PCAP_ERR_STARTCAPTURE, NULL);
if (addrinfo)
freeaddrinfo(addrinfo);
if (threaddata)
pthread_cancel(*threaddata);
if (sockdata)
sock_close(sockdata, NULL, 0);
// Check if all the data has been read; if not, discard the data in excess
if (nread != plen)
sock_discard(sockctrl, plen - nread, NULL, 0);
if (fp)
{
pcap_close(fp);
fp= NULL;
}
return NULL;
}
/*
\param plen: the length of the current message (needed in order to be able
to discard excess data in the message, if present)
*/
int daemon_opensource(SOCKET sockctrl, char *source, int srclen, uint32 plen, char *errbuf)
{
pcap_t *fp= NULL; // pcap_t main variable
unsigned int nread; // number of bytes of the payload read from the socket
char sendbuf[RPCAP_NETBUF_SIZE]; // temporary buffer in which data to be sent is buffered
int sendbufidx= 0; // index which keeps the number of bytes currently buffered
struct rpcap_openreply *openreply; // open reply message
strcpy(source, PCAP_SRC_IF_STRING);
if (srclen <= (int) (strlen(PCAP_SRC_IF_STRING) + plen) )
{
rpcap_senderror(sockctrl, "Source string too long", PCAP_ERR_OPEN, NULL);
return -1;
}
if ( (nread= sock_recv(sockctrl, &source[strlen(PCAP_SRC_IF_STRING)], plen, SOCK_RECEIVEALL_YES, errbuf, PCAP_ERRBUF_SIZE)) == -1)
return -1;
// Check if all the data has been read; if not, discard the data in excess
if (nread != plen)
sock_discard(sockctrl, plen - nread, NULL, 0);
// Puts a '0' to terminate the source string
source[strlen(PCAP_SRC_IF_STRING) + plen]= 0;
// Open the selected device
// This is a fake open, since we do that only to get the needed parameters, then we close the device again
if ( (fp= pcap_open(source,
1500 /* fake snaplen */,
0 /* no promis */,
1000 /* fake timeout */,
NULL /* local device, so no auth */,
errbuf)) == NULL)
{
rpcap_senderror(sockctrl, errbuf, PCAP_ERR_OPEN, NULL);
return -1;
}
// Now, I can send a RPCAP open reply message
if ( sock_bufferize(NULL, sizeof(struct rpcap_header), NULL, &sendbufidx,
RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, errbuf, PCAP_ERRBUF_SIZE) == -1)
goto error;
rpcap_createhdr( (struct rpcap_header *) sendbuf, RPCAP_MSG_OPEN_REPLY, 0, sizeof(struct rpcap_openreply) );
openreply= (struct rpcap_openreply *) &sendbuf[sendbufidx];
if ( sock_bufferize(NULL, sizeof(struct rpcap_openreply), NULL, &sendbufidx,
RPCAP_NETBUF_SIZE, SOCKBUF_CHECKONLY, errbuf, PCAP_ERRBUF_SIZE) == -1)
goto error;
memset(openreply, 0, sizeof(struct rpcap_openreply) );
openreply->linktype= htonl(fp->linktype);
openreply->tzoff= htonl(fp->tzoff);
if ( sock_send(sockctrl, sendbuf, sendbufidx, errbuf, PCAP_ERRBUF_SIZE) == -1)
goto error;
// I have to close the device again, since it has been opened with wrong parameters
pcap_close(fp);
fp= NULL;
return 0;
error:
if (fp)
{
pcap_close(fp);
fp= NULL;
}
return -1;
}
/*!
\brief It checks if the authentication credentials supplied by the user are valid.
This function is called each time the rpcap daemon starts a new serving thread.
It reads the authentication message from the network and it checks that the
user information are valid.
\param sockctrl: the socket if of the control connection.
\param nullAuthAllowed: '1' if the NULL authentication is allowed.
\param errbuf: a user-allocated buffer in which the error message (if one) has to be written.
\return '0' if everything is fine, '-1' if an unrecoverable error occurred.
The error message is returned in the 'errbuf' variable.
'-2' is returned in case the authentication failed or in case of a recoverable error (like
wrong version). In that case, 'errbuf' keeps the reason of the failure. This provides
a way to know that the connection does not have to be closed.
In case the message is a 'CLOSE' or an 'ERROR', it returns -3. The error can be due to a
connection refusal in active mode, since this host cannot be allowed to connect to the remote
peer.
*/
int daemon_checkauth(SOCKET sockctrl, int nullAuthAllowed, char *errbuf)
{
struct rpcap_header header; // RPCAP message general header
int retval; // generic return value
unsigned int nread; // number of bytes of the payload read from the socket
struct rpcap_auth auth; // RPCAP authentication header
char *string1, *string2; // two strings exchanged by the authentication message
unsigned int plen; // length of the payload
int retcode; // the value we have to return to the caller
if (sock_recv(sockctrl, (char *) &header, sizeof(struct rpcap_header), SOCK_RECEIVEALL_YES, errbuf, PCAP_ERRBUF_SIZE) == -1)
return -1;
plen= ntohl(header.plen);
retval= rpcap_checkmsg(errbuf, sockctrl, &header,
RPCAP_MSG_AUTH_REQ,
RPCAP_MSG_CLOSE,
0);
if (retval != RPCAP_MSG_AUTH_REQ)
{
switch (retval)
{
case -3: // Unrecoverable network error
return -1; // Do nothing; just exit; the error code is already into the errbuf
case -2: // The other endpoint send a message that is not allowed here
case -1: // The other endpoint has a version number that is not compatible with our
return -2;
case RPCAP_MSG_CLOSE:
{
// Check if all the data has been read; if not, discard the data in excess
if (ntohl(header.plen) )
{
if (sock_discard(sockctrl, ntohl(header.plen), NULL, 0) )
{
retcode= -1;
goto error;
}
}
return -3;
};
case RPCAP_MSG_ERROR:
return -3;
default:
{
SOCK_ASSERT("Internal error.", 1);
retcode= -2;
goto error;
};
}
}
// If it comes here, it means that we have an authentication request message
if ( (nread= sock_recv(sockctrl, (char *) &auth, sizeof(struct rpcap_auth), SOCK_RECEIVEALL_YES, errbuf, PCAP_ERRBUF_SIZE)) == -1)
{
retcode= -1;
goto error;
}
switch (ntohs(auth.type) )
{
case RPCAP_RMTAUTH_NULL:
{
if (!nullAuthAllowed)
{
snprintf(errbuf, PCAP_ERRBUF_SIZE, "Authentication failed; NULL autentication not permitted.");
retcode= -2;
goto error;
}
break;
}
case RPCAP_RMTAUTH_PWD:
{
int len1, len2;
len1= ntohs(auth.slen1);
len2= ntohs(auth.slen2);
string1= (char *) malloc (len1 + 1);
string2= (char *) malloc (len2 + 1);
if ( (string1 == NULL) || (string2 == NULL) )
{
snprintf(errbuf, PCAP_ERRBUF_SIZE, "malloc() failed: %s", pcap_strerror(errno));
retcode= -1;
goto error;
}
if ( (nread+= sock_recv(sockctrl, string1, len1, SOCK_RECEIVEALL_YES, errbuf, PCAP_ERRBUF_SIZE)) == -1)
{
retcode= -1;
goto error;
}
if ( (nread+= sock_recv(sockctrl, string2, len2, SOCK_RECEIVEALL_YES, errbuf, PCAP_ERRBUF_SIZE)) == -1)
{
retcode= -1;
goto error;
}
string1[len1]= 0;
string2[len2]= 0;
if (daemon_AuthUserPwd(string1, string2, errbuf) )
{
retcode= -2;
goto error;
}
break;
}
default:
snprintf(errbuf, PCAP_ERRBUF_SIZE, "Authentication type not recognized.");
retcode= -2;
goto error;
}
// Check if all the data has been read; if not, discard the data in excess
if (nread != plen)
{
if (sock_discard(sockctrl, plen - nread, NULL, 0) )
{
retcode= -1;
goto error;
}
}
rpcap_createhdr(&header, RPCAP_MSG_AUTH_REPLY, 0, 0);
// Send the ok message back
if ( sock_send(sockctrl, (char *) &header, sizeof (struct rpcap_header), errbuf, PCAP_ERRBUF_SIZE) == -1)
{
retcode= -1;
goto error;
}
return 0;
error:
// Check if all the data has been read; if not, discard the data in excess
if (nread != plen)
sock_discard(sockctrl, plen - nread, NULL, 0);
return retcode;
}
