/**
* op.c
* Onion Proxy
*
* Matej Pfajfar <mp292@cam.ac.uk>
*/
/*
* Changes :
* $Log$
* Revision 1.1 2002/06/26 22:45:50 arma
* Initial revision
*
* Revision 1.37 2002/06/14 20:45:56 mp292
* *** empty log message ***
*
* Revision 1.36 2002/04/02 14:28:01 badbytes
* Final finishes.
*
* Revision 1.35 2002/04/02 10:21:07 badbytes
* *** empty log message ***
*
* Revision 1.34 2002/03/29 08:35:12 badbytes
* Link encryption is now done on the entire cell header for simplicity.
*
* Revision 1.33 2002/03/28 17:57:59 badbytes
* Bug fix.
*
* Revision 1.32 2002/03/28 11:01:43 badbytes
* Now does link-encryption and link-padding.
*
* Revision 1.31 2002/03/12 23:40:32 mp292
* Started on op<->router connection padding.
*
* Revision 1.30 2002/01/29 02:22:58 mp292
* Put a timeout on all network I/O.
*
* Revision 1.29 2002/01/26 23:01:55 mp292
* Reviewed according to Secure-Programs-HOWTO.
*
* Revision 1.28 2002/01/18 20:42:06 mp292
* Reflects changes to common/onion.c:new_route()
*
* Revision 1.27 2002/01/17 23:49:15 mp292
* Added size of public key to one of the debugging messages.
*
* Revision 1.26 2002/01/16 23:01:58 mp292
* First phase of system testing completed (main functionality).
*
* Revision 1.25 2002/01/16 17:01:56 mp292
* There was a bug in checking whether the incoming connection is local or not.
*
* Revision 1.24 2002/01/16 16:09:32 mp292
* A pointer cast was missing. Fixed.
*
* Revision 1.23 2002/01/14 13:05:39 badbytes
* System testing in progress.
*
* Revision 1.22 2002/01/11 15:47:25 badbytes
* *** empty log message ***
*
* Revision 1.21 2002/01/09 09:18:35 badbytes
* Now handles EINTR error from accept().
*
* Revision 1.20 2002/01/09 07:57:18 badbytes
* Ciphers got out of sync, hopefully fixed.
*
* Revision 1.19 2001/12/19 11:15:41 badbytes
* Corrected AF_INET to PF_INET in socket() calls.
*
* Revision 1.18 2001/12/19 08:38:38 badbytes
* Zombie problems hopefully fixed.
*
* Revision 1.17 2001/12/19 08:29:29 badbytes
* Tested. Still some problems with zombies in both op and smtpap.
*
* Revision 1.16 2001/12/18 15:51:58 badbytes
* Connection with onion router established. Will continue testing tomorrow.
*
* Revision 1.15 2001/12/18 14:12:05 badbytes
* Tested up to connect() to onion router.
*
* Revision 1.14 2001/12/18 12:21:11 badbytes
* Forgot to convert port to network order :-)
*
* Revision 1.13 2001/12/18 11:52:27 badbytes
* Coding completed. Proceeding to test.
*
* Revision 1.12 2001/12/17 13:36:15 badbytes
* Writing handle_connection()
*
* Revision 1.11 2001/12/17 08:42:44 badbytes
* getrouters() now returns an array of routers and also writes the length of the array to an int*.
*
* Revision 1.10 2001/12/14 14:45:13 badbytes
* Added range checking for CoinWeight.
*
* Revision 1.9 2001/12/14 14:08:50 badbytes
* getrouters() now returns an array of pointers rather than a linked list
*
* Revision 1.8 2001/12/14 13:31:20 badbytes
* *** empty log message ***
*
* Revision 1.7 2001/12/14 13:17:12 badbytes
* Corrected references to types.h
*
* Revision 1.6 2001/12/14 13:00:30 badbytes
* Changed my mind, routers.c and routers.h stay where they are :-)
*
* Revision 1.5 2001/12/14 12:56:55 badbytes
* Moved routers* to common/
*
* Revision 1.4 2001/12/14 12:42:50 badbytes
* References to onion.h and onion.o now point to the common/ directory.
*
* Revision 1.3 2001/12/14 12:40:26 badbytes
* Was being stupid - op doesn't need a private key!! Have removed ...
*
* Revision 1.2 2001/12/14 11:27:16 badbytes
* Configuration and server setup completed.
*
* Revision 1.1 2001/12/13 15:15:11 badbytes
* Started coding the onion proxy.
*
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <errno.h>
#include <ctype.h>
#include <stdio.h>
#include <unistd.h>
#include <signal.h>
#include <wait.h>
#include <openssl/err.h>
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/evp.h>
#include <openssl/rand.h>
#include "../common/log.h"
#include "../common/version.h"
#include "../common/onion.h"
#include "../common/utils.h"
#include "../common/cell.h"
#include "../common/scheduler.h"
#include "config.h"
#include "routers.h"
#include "args.h"
#include "auth.h"
#include "op.h"
#include "ss.h"
#include "crypto.h"
#include "buffers.h"
/* global variables */
/* default logging threshold */
int loglevel = LOG_ERR;
struct timeval conn_tout;
struct timeval *conn_toutp = &conn_tout;
/* valid command-line options */
static char *args = "hf:p:l:";
/* valid config file options */
static config_opt_t options[] =
{
{"RouterFile", CONFIG_TYPE_STRING, {0}, 0},
{"CoinWeight", CONFIG_TYPE_DOUBLE, {0}, 0},
{"MaxConn", CONFIG_TYPE_INT, {0}, 0},
{"ConnTimeout", CONFIG_TYPE_INT, {0}, 0},
{"Bandwidth", CONFIG_TYPE_INT, {0}, 0},
{0}
};
enum opts {
RouterFile=0, CoinWeight, MaxConn, ConnTimeout, Bandwidth
};
int connections = 0; /* number of active connections */
/* local host info */
struct hostent *local_host;
char local_hostname[512];
struct sockaddr_in local, remote; /* local and remote address info */
struct sockaddr_in or_addr; /* onion router address */
int request_sock; /* where we listen for connections */
int new_sock; /* for accepted connections */
int or_sock; /* for connecting to the first onion router */
/* router array */
routent_t **routerarray = NULL;
int rarray_len = 0;
/* end of global variables */
void send_to_router(int s,unsigned char **outbuf, size_t *outbuflen, size_t *outbuf_dataoffset, size_t *outbuf_datalen, struct timeval *lastsend, struct timeval *interval, sched_t *scheduler, EVP_CIPHER_CTX *ctx)
{
int retval;
int cells;
int datacells;
int paddingcells;
int i;
int x;
char *px;
struct timeval now;
cell_t cipher;
cell_t *padding;
int cipherlen;
unsigned long elapsed;
/* calculate the number of cells that need to be sent */
retval = gettimeofday(&now,NULL);
if (retval == -1)
{
log(LOG_ERR,"Could not get current time!");
return;
}
elapsed = 1000000*(now.tv_sec-lastsend->tv_sec) + now.tv_usec-lastsend->tv_usec;
if (elapsed < 1000000)
{
cells = ((options[Bandwidth].r.i) * 512) / /* number of bytes per second, divided by two */
(1000000/elapsed); /* fractions of second since last send */
}
else
{
cells = ((options[Bandwidth].r.i) * 512) * /* number of bytes per second, divided by two */
(elapsed/1000000); /* 1/fractions of second since last send */
}
cells /= sizeof(cell_t);
datacells = (*outbuf_datalen)/sizeof(cell_t); /* number of data cells available */
if (datacells > cells)
datacells = cells;
paddingcells = cells - datacells;
/* send the data cells first */
for (i=0; i<datacells; i++)
{
/* link-encrypt the cell header */
printf("Cell header plaintext: ");
for(x=0;x<8;x++) {
printf("%u ",*(char *)(*outbuf+*outbuf_dataoffset+x));
}
printf("\n");
retval = EVP_EncryptUpdate(ctx, (unsigned char *)&cipher, &cipherlen, *outbuf+*outbuf_dataoffset, 8);
if (!retval)
{
log(LOG_ERR,"Link encryption failed. Exiting.");
exit(-1);
}
printf("Cell header crypttext: ");
px = (char *)&cipher;
for(x=0;x<8;x++) {
printf("%u ",px[x]);
}
printf("\n");
/* copy the payload */
memcpy((void *)cipher.payload, (void *)(*outbuf+*outbuf_dataoffset+8), CELL_PAYLOAD_SIZE);
/* send the cell */
log(LOG_DEBUG,"send_to_router(): Trying to send a data/create cell to router.");
retval = write_tout(s,(unsigned char *)&cipher, sizeof(cell_t), conn_toutp);
if (retval < sizeof(cell_t))
{
log(LOG_ERR,"Connection to the router seems to be lost. Exiting.");
exit(-1);
}
*outbuf_dataoffset += sizeof(cell_t);
*outbuf_datalen -= sizeof(cell_t);
}
/* send padding */
for (i=0; i<cells-datacells; i++)
{
padding = new_padding_cell();
if (!padding)
{
log(LOG_ERR,"Memory allocation error. Exiting.");
exit(-1);
}
/* link encrypt the cell header */
retval = EVP_EncryptUpdate(ctx, (unsigned char *)&cipher, &cipherlen, (unsigned char *)padding, 8);
if (!retval)
{
log(LOG_ERR,"Link encryption failed. Exiting.");
exit(-1);
}
/* copy the payload */
memcpy((void *)cipher.payload, (void *)((unsigned char *)padding+8), CELL_PAYLOAD_SIZE);
/* send the cell */
log(LOG_DEBUG,"send_to_router(): Trying to send a padding cell to router.");
retval = write_tout(s, (unsigned char *)&cipher, sizeof(cell_t), conn_toutp);
if (retval < sizeof(cell_t))
{
log(LOG_ERR,"Connection to the router seems to be lost. Exiting.");
exit(-1);
}
free((void *)padding);
}
/* update scheduler state, if we've sent anything to the router */
if (cells)
{
retval = update_sched_entry(scheduler, *lastsend, *interval, now, *interval);
if (retval == -1)
{
log(LOG_ERR,"Scheduler error. Exiting.");
exit(-1);
}
memcpy((void *)lastsend,(void *)&now, sizeof(struct timeval));
}
}
/* deal with a client */
int handle_connection()
{
int retval = 0;
int routelen = 0; /* length of the route */
unsigned int *route = NULL; /* hops in the route as an array of indexes into rarray */
routent_t *firsthop = NULL;
uint32_t aci; /* ACI for this connection */
unsigned char *onion = NULL; /* holds the onion */
int onionlen = 0; /* onion length in host order */
crypt_path_t **cpath = NULL; /* defines the crypt operations that need to be performed on incoming/outgoing data */
char *dest_addr = NULL; /* destination address in ASCII format */
int dest_addrlen = 0;
char *dest_port = NULL; /* destination port in ASCII format */
int dest_portlen = 0;
ss_t *ss; /* standard structure */
uint32_t router_addr_net; /* address of the first onion router in network order */
unsigned char inbuf[1024]; /* buffer for forwarding data between ap and or */
unsigned char *outbuf = NULL; /* buffer for cells which are to be transmitted to the first core onion router in the route */
size_t outbuflen = 0;
size_t outbuf_dataoffset = 0; /* offset to the beginning of the data */
size_t outbuf_datalen = 0; /* length of the data stored in the buffer */
cell_t cellbuf;
int cellbuflen = 0;
struct timeval lastsend; /* time of last transmission to the onion router */
struct timeval interval; /* transmission interval */
/* link encryption */
unsigned char f_session_key[8];
unsigned char f_session_iv[8] = {0,0,0,0,0,0,0,0};
unsigned char b_session_key[8];
unsigned char b_session_iv[8] = {0,0,0,0,0,0,0,0};
EVP_CIPHER_CTX f_ctx;
EVP_CIPHER_CTX b_ctx;
/* scheduler */
sched_t *scheduler;
/* for use with select() */
fd_set rmask, mask;
int maxfd;
struct timeval *timeout;
/* get the standard structure */
retval = process_ss(new_sock, conn_toutp, &ss,&dest_addr, &dest_addrlen, &dest_port, &dest_portlen);
if (retval == -1)
{
log(LOG_ERR,"Error processing the standard structure.");
return -1;
}
log(LOG_DEBUG,"handle_connection() : Destination = %s:%s",dest_addr,dest_port);
/* choose a route */
route = (unsigned int *)new_route(options[CoinWeight].r.d, routerarray,rarray_len, &routelen);
if (!route)
{
log(LOG_ERR,"Error choosing a route through the OR network.");
return -1;
}
log(LOG_DEBUG,"handle_connection() : Chosen a route of length %u : ",routelen);
for (retval=routelen-1;retval>=0;retval--)
{
log(LOG_DEBUG,"handle_connection() : %u : %s:%u, %u",routelen-retval,(routerarray[route[retval]])->address,ntohs((routerarray[route[retval]])->port),RSA_size((routerarray[route[retval]])->pkey));
}
/* allocate memory for the crypt path */
cpath = malloc(routelen * sizeof(crypt_path_t *));
if (!cpath)
{
log(LOG_ERR,"Error allocating memory.");
free(route);
return -1;
}
/* create an onion and calculate crypto keys */
onion = create_onion(routerarray,rarray_len,route,routelen,&onionlen,cpath);
if (!onion)
{
log(LOG_ERR,"Error creating an onion.");
free(route);
return -1;
}
log(LOG_DEBUG,"handle_connection() : Created an onion of size %u bytes.",onionlen);
log(LOG_DEBUG,"handle_connection() : Crypt path :");
for (retval=0;retval<routelen;retval++)
{
log(LOG_DEBUG,"handle_connection() : %u/%u",(cpath[retval])->forwf, (cpath[retval])->backf);
}
/* connect to first onion router */
or_sock = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
if (or_sock < 0)
{
free(route);
free(onion);
free(cpath);
close(new_sock);
log(LOG_ERR,"Error creating socket.");
return -1;
}
log(LOG_DEBUG,"handle_connection() : Socket created.");
firsthop = routerarray[route[routelen-1]];
memset((void *)&or_addr,0,sizeof(or_addr));
or_addr.sin_family=AF_INET;
or_addr.sin_port=firsthop->entry_port;
router_addr_net = firsthop->addr;
memcpy(&or_addr.sin_addr,&router_addr_net,sizeof(struct sockaddr_in));
log(LOG_DEBUG,"handle_connection() : Trying to connect to %s:%u",inet_ntoa(or_addr.sin_addr), ntohs(or_addr.sin_port));
retval = connect(or_sock,(struct sockaddr *)&or_addr, sizeof(or_addr));
if (retval == -1)
{
log(LOG_ERR,"Could not connect to onion router.");
free(route);
free(onion);
free(cpath);
close(or_sock);
close(new_sock);
return -1;
}
log(LOG_DEBUG,"handle_connection() : Connected to first onion router.");
/* send session key and bandwidth info */
retval = send_auth(or_sock, options[Bandwidth].r.i, firsthop->pkey, f_session_key, b_session_key);
if (retval == -1)
{
close(or_sock);
close(new_sock);
log(LOG_ERR,"Lost connection to an onion router. Exiting.");
return -1;
}
/* initialize crypto engines */
EVP_CIPHER_CTX_init(&f_ctx);
EVP_CIPHER_CTX_init(&b_ctx);
EVP_EncryptInit(&f_ctx, EVP_des_ofb(), f_session_key, f_session_iv);
EVP_DecryptInit(&b_ctx, EVP_des_ofb(), b_session_key, b_session_iv);
/* chose an ACI */
do
{
retval = RAND_pseudo_bytes((unsigned char *)&aci, 2);
if (retval==-1)
{
log(LOG_ERR,"Random data generator doesn't seem to work. Exiting.");
return -1;
}
} while(!aci); /* don't allow zero ACIs */
log(LOG_DEBUG,"handle_connection() : ACI %u chosen.",aci);
/* initialize last time of transmission to now */
retval = gettimeofday(&lastsend, NULL);
if (retval == -1)
{
log(LOG_ERR,"Could not get current time.");
return -1;
}
/* calculate the transmission interval */
interval.tv_sec = 0;
interval.tv_usec = 250000/options[Bandwidth].r.i;
/* initialize the scheduler */
scheduler = new_sched();
if (!scheduler)
{
log(LOG_ERR,"Could not initialize scheduler.");
return -1;
}
retval = add_sched_entry(scheduler, lastsend, interval);
if (retval == -1)
{
log(LOG_ERR,"Could not initialize scheduler.");
return -1;
}
timeout = NULL;
/* write the onion into the output buffer */
retval = buffer_create(aci, (unsigned char *)onion, onionlen, &outbuf, &outbuflen, &outbuf_dataoffset, &outbuf_datalen, cpath, routelen);
if (retval == -1)
{
log(LOG_DEBUG,"handle_connection() : Could not buffer the onion.");
close(or_sock);
return -1;
}
log(LOG_DEBUG,"handle_connection() : Onion buffered for output.");
/* send standard structure */
log(LOG_DEBUG,"handle_connection() : Calling send_crypt ... routelen=%u, sizeof(SS) = %u",routelen,sizeof(ss_t));
retval = buffer_data(aci, (unsigned char *)ss, sizeof(ss_t), &outbuf, &outbuflen, &outbuf_dataoffset, &outbuf_datalen, cpath, routelen);
if (retval == -1)
{
log(LOG_DEBUG,"handle_connection() : Could not buffer the standard structure for output.");
close(or_sock);
return -1;
}
log(LOG_DEBUG,"handle_connection() : Buffered the standard structure header.");
retval = buffer_data(aci, dest_addr,dest_addrlen, &outbuf, &outbuflen, &outbuf_dataoffset, &outbuf_datalen, cpath, routelen);
if (retval == -1)
{
log(LOG_DEBUG,"handle_connection() : Could not buffer the standard structure (dest. address) for output.");
close(or_sock);
return -1;
}
log(LOG_DEBUG,"handle_connection() : Buffered the destination address.");
retval = buffer_data(aci, dest_port, dest_portlen, &outbuf, &outbuflen, &outbuf_dataoffset, &outbuf_datalen, cpath, routelen);
if (retval == -1)
{
log(LOG_DEBUG,"handle_connection() : Could not buffer the standard structure (dest. port) for output.");
close(or_sock);
return -1;
}
log(LOG_DEBUG,"handle_connection() : Buffered the destination port.");
/* forward data in both directions, crypt as necessary */
/* use select() */
FD_ZERO(&mask);
FD_SET(new_sock, &mask);
FD_SET(or_sock, &mask);
if (new_sock > or_sock)
maxfd = new_sock;
else
maxfd = or_sock;
while(1)
{
rmask = mask;
/* delete old timeout */
if (timeout)
free((void *)timeout);
/* get the new one */
retval = sched_trigger(scheduler, &timeout);
if (retval == -1)
{
log(LOG_DEBUG,"Scheduler error.");
break;
}
retval = select(maxfd+1,&rmask,NULL,NULL,timeout);
if (retval < 0)
{
log(LOG_DEBUG,"handle_connection() : select() returned negative integer");
break;
}
if (FD_ISSET(new_sock,&rmask))
{
log(LOG_DEBUG,"handle_connection() : FD_ISSET(new_sock)");
retval = read_tout(new_sock, inbuf, 1024, 0, conn_toutp);
if (retval <= 0)
{
log(LOG_DEBUG,"handle_connection() : Received EOF on new_sock.");
break;
}
log(LOG_DEBUG,"handle_connection() : Received %u bytes from client.",retval);
retval = buffer_data(aci, inbuf, retval, &outbuf, &outbuflen, &outbuf_dataoffset, &outbuf_datalen, cpath, routelen);
if (retval < 0)
{
log(LOG_DEBUG,"handle_connection() : Could not buffer data for output to OR.");
break;
}
log(LOG_DEBUG,"handle_connection() : Buffered %u bytes for output to the OR.",retval);
}
if (FD_ISSET(or_sock, &rmask))
{
log(LOG_DEBUG,"handle_connection() : FD_ISSET(or_sock)");
/* read the remainder of the cell (or whatever we can get) */
retval = read_tout(or_sock, ((unsigned char *)&cellbuf)+cellbuflen, sizeof(cell_t) - cellbuflen, 0, conn_toutp);
if (retval <= 0)
{
log(LOG_DEBUG,"handle_connection() : Received EOF on or_sock.");
break;
}
log(LOG_DEBUG,"handle_connection() : Received %u bytes from router.",retval);
cellbuflen += retval;
if (cellbuflen == sizeof(cell_t)) /* received an entire cell */
{
/* link decrypt the cell header */
retval = EVP_DecryptUpdate(&b_ctx, (unsigned char *)inbuf, &cellbuflen, (unsigned char *)&cellbuf, 8);
if (!retval)
{
log(LOG_ERR,"Decryption error. Closing the connection and exiting.");
break;
}
if (((cell_t *)inbuf)->command == CELL_PADDING) /* padding, discard */
{
log(LOG_DEBUG,"Received a PADDING cell. Discarding.");
; /* discard */
}
else if (((cell_t *)inbuf)->command == CELL_DATA) /* only process DATA cells , discard otherwise */
{
/* decrypt the payload length */
retval = crypt_b((unsigned char *)&((cell_t *)inbuf)->length, 1, cpath, routelen);
if (retval == -1)
{
log(LOG_ERR,"Decryption error. Closing the connection and exiting.");
break;
}
/* decrypt the payload */
retval = crypt_b((unsigned char *)cellbuf.payload, CELL_PAYLOAD_SIZE, cpath, routelen);
if (retval == -1)
{
log(LOG_ERR,"Decryption error. Closing the connection and exiting.");
break;
}
/* send the payload to the application proxy */
retval = write_tout(new_sock, (unsigned char *)cellbuf.payload, ((cell_t *)inbuf)->length, conn_toutp);
if (retval < ((cell_t *)inbuf)->length)
{
log(LOG_ERR,"Connection to the application proxy seems to be lost.");
break;
}
log(LOG_DEBUG,"handle_connection() : Sent %u bytes to client.",retval);
}
else
log(LOG_DEBUG,"handle_connection() : Recived cell has incorrect command or ACI. Discarding.");
cellbuflen = 0; /* get ready for the next cell */
}
}
/* send cells to the router */
send_to_router(or_sock,&outbuf, &outbuflen, &outbuf_dataoffset, &outbuf_datalen, &lastsend, &interval, scheduler, &f_ctx);
}
/* clean up */
log(LOG_DEBUG,"handle_connection() : handle_connection() exiting.");
close(or_sock);
return 0;
}
/* used for reaping zombie processes */
void sigchld_handler(int s)
{
while (wait(NULL) > 0);
connections--;
}
int main(int argc, char *argv[])
{
int one = 1;
int retval = 0;
char *cp; /* temporary storage */
int i=0; /* iteration counter */
char *conf_filename = NULL; /* configuration file */
size_t sin_size; /* for accept() calls */
u_short p; /* onion proxy port */
/* used for reaping zombie processes */
struct sigaction sa;
int islocal = 0; /* is the incoming connection local? */
struct rlimit cd_limit; /* resource limit to prevent core dumps */
/* prevent core dump */
retval = getrlimit(RLIMIT_CORE, &cd_limit);
if (retval == -1)
{
log(LOG_ERR,"Could not tell the OS to prevent core dumps for the process.");
return -1;
}
cd_limit.rlim_cur = 0;
retval = setrlimit(RLIMIT_CORE, &cd_limit);
if (retval == -1)
{
log(LOG_ERR,"Could not tell the OS to prevent core dumps for the process.");
return -1;
}
/* get command-line arguments */
retval = getargs(argc,argv,args,&p,&conf_filename,&loglevel);
if (retval == -1)
{
log(LOG_ERR,"Error processing command-line arguments.");
exit(1);
}
/* load config file */
retval = getconfig(conf_filename,options);
if (retval == -1)
{
log(LOG_ERR,"Error loading configuration file.");
exit(1);
}
if (options[RouterFile].err != 1)
{
log(LOG_ERR,"RouterFile option required, but not found.");
exit(1);
}
if (options[CoinWeight].err == -1)
{
log(LOG_ERR,"Error reading the CoinWeight option.");
exit(1);
}
if (options[CoinWeight].err == 0)
{
/* this is optional, so if not found, set default value */
options[CoinWeight].r.d = OP_DEFAULT_COIN_WEIGHT;
}
else if ((options[CoinWeight].r.d < 0) || (options[CoinWeight].r.d >= 1))
{
/* must be a value in [0,1) */
log(LOG_ERR,"CoinWeight option must be >= 0 and < 1.");
exit(1);
}
if (options[Bandwidth].err == 0)
{
/* optional, set to default */
options[Bandwidth].r.i = OP_DEFAULT_BANDWIDTH;
}
else if (options[Bandwidth].r.i <= 0)
{
log(LOG_ERR,"The Bandwidth option must be an integer greater than zero.");
exit(1);
}
if (options[ConnTimeout].err != 1)
{
conn_tout.tv_sec = OP_DEFAULT_CONN_TIMEOUT;
conn_tout.tv_usec = 0;
}
else
{
if (!options[ConnTimeout].r.i)
conn_toutp = NULL;
else
conn_tout.tv_sec = options[ConnTimeout].r.i;
conn_tout.tv_usec = 0;
}
/* load the routers file */
routerarray = getrouters(options[RouterFile].r.str,&rarray_len);
if (!routerarray)
{
log(LOG_ERR,"Error loading router list.");
exit(1);
}
/* get local address so that we know where to allow connections from*/
retval = gethostname(local_hostname, (size_t)512);
if (retval < 0)
{
log(LOG_ERR,"Error getting local hostname.");
return -1;
}
local_host = gethostbyname(local_hostname);
if (!local_host)
{
log(LOG_ERR,"Error getting local address.");
return -1;
}
log(LOG_DEBUG,"main() : Got local address : %s.",local_hostname);
/* get the server up and running */
request_sock = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
if (request_sock < 0)
{
log(LOG_ERR,"Error opening socket.");
return -1;
}
setsockopt(request_sock, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
log(LOG_DEBUG,"main() : Socket opened.");
memset((void *)&local,0,sizeof(local)); /* clear the structure first */
/* set up the sockaddr_in structure */
local.sin_family=AF_INET;
local.sin_addr.s_addr = INADDR_ANY;
local.sin_port=htons(p);
/* bind it to the socket */
retval = bind(request_sock,(struct sockaddr *)&local, sizeof(local));
if (retval < 0)
{
log(LOG_ERR,"Error binding socket to local port %d.",p);
return retval;
}
log(LOG_DEBUG,"main() : Socket bound to port %d.",p);
/* listen for connections */
retval = listen(request_sock,SOMAXCONN);
if (retval < 0)
{
log(LOG_ERR,"Could not listen for connections.");
return retval;
}
log(LOG_DEBUG,"main() : Listening for connections.");
/* server should now be up and running */
/* install the signal handler for making sure zombie processes are killed */
sa.sa_handler = sigchld_handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART;
retval = sigaction(SIGCHLD,&sa,NULL);
if (retval < 0)
{
log(LOG_ERR,"Could not install a signal handler.");
return -1;
}
/* main server loop */
/* I use a forking server technique - this isn't the most efficient way to do it,
* but it is simpler. */
while(1)
{
sin_size = sizeof(struct sockaddr_in);
new_sock = accept(request_sock,(struct sockaddr *)&remote,&sin_size);
if (new_sock == -1)
{
if (errno != EINTR)
log(LOG_ERR,"Could not accept socket connection.");
else
log(LOG_DEBUG,"main() : Interrupt received.");
continue;
}
if (connections == options[MaxConn].r.i)
{
close(new_sock);
log(LOG_NOTICE,"Maximum connection limit exceeded. Rejecting incoming request.");
}
connections++;
log(LOG_DEBUG,"main() : Accepted a connection from %s.",inet_ntoa(remote.sin_addr));
/* see if the connection is local, otherwise reject */
/* first check that the connection is from the local host, otherwise reject */
if (*(uint32_t *)&remote.sin_addr == inet_addr("127.0.0.1"))
islocal=1;
for (i=0; (local_host->h_addr_list[i] != NULL) && (!islocal); i++)
{
cp = local_host->h_addr_list[i];
if (!memcmp(&remote.sin_addr, cp,sizeof(struct in_addr)))
islocal = 1;
}
if (!islocal)
{
log(LOG_DEBUG,"main() : Incoming connection is not local. Will reject.");
close(new_sock);
}
else
{
log(LOG_DEBUG,"main() : Incoming connection seems to be local. Will accept.");
/* fork a process to deal with the customer */
if (!fork()) /* this is the child process */
{
close(request_sock); /* the child doesn't need the request socket anymore */
/* Main logic of op. */
retval = handle_connection();
log(LOG_DEBUG,"main() : Handle connection returned %d.",retval);
/* End main logic */
exit(retval); /* done, exit */
}
close(new_sock); /* don't need this anymore */
}
}
return retval;
}