server/socket/lowlevel.c


/*
 * static char *rcsid_sockets_c =
 *    "$Id$";
 */

/*
    CrossFire, A Multiplayer game for X-windows

    Copyright (C) 1992 Frank Tore Johansen

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

    The author can be reached via e-mail to mark@pyramid.com
*/

/**
 * \file
 * Low-level socket-related functions.
 *
 * \date 2003-12-02
 *
 * Contains some base functions that both the client and server
 * can use.  As such, depending what we are being compiled for will
 * determine what we can include.  the client is designed have
 * CFCLIENT defined as part of its compile flags.
 */

#include <global.h>
#include <newclient.h>
#include <sproto.h>

#ifdef __linux__
# include <sys/types.h>
# include <sys/socket.h>
# include <netinet/in.h>
# define TCP_HZ 1000 // sorry...
# include <netinet/tcp.h>
#endif

// use a really low timeout, as it doesn't cost any bandwidth, and you can
// easily die in 20 seconds... (actually, 20s after the last data was sent
#define SOCKET_TIMEOUT 20

void Socket_Flush (NewSocket *ns)
{
#ifdef __linux__
  int val;
  val = 0; setsockopt (ns->fd, IPPROTO_TCP, TCP_CORK, &val, sizeof (val));
  val = 1; setsockopt (ns->fd, IPPROTO_TCP, TCP_CORK, &val, sizeof (val));

  // check time of last ack, and, if too old, kill connection
  struct tcp_info tcpi;
  socklen_t len = sizeof (tcpi);
  if (!getsockopt (ns->fd, IPPROTO_TCP, TCP_INFO, &tcpi, &len) && len == sizeof (tcpi))
    {
      unsigned int diff = tcpi.tcpi_last_ack_recv - tcpi.tcpi_last_data_sent;

      if (SOCKET_TIMEOUT * TCP_HZ < diff && diff < 0x80000000UL)
        {
          LOG (llevDebug, "Connection on fd %d closed due to ack timeout (%u/%u)\n", ns->fd,
               (unsigned)tcpi.tcpi_last_ack_recv, (unsigned)tcpi.tcpi_last_data_sent);
          ns->status = Ns_Dead;
        }
    }
#endif
}

/***********************************************************************
 *
 * SockList functions/utilities
 *
 **********************************************************************/

void SockList_Init(SockList *sl)
{
    sl->len=0;
    sl->buf=NULL;
}

void SockList_AddChar(SockList *sl, char c)
{
    sl->buf[sl->len]=c;
    sl->len++;
}

void SockList_AddShort(SockList *sl, uint16 data)
{
    sl->buf[sl->len++]= (data>>8)&0xff;
    sl->buf[sl->len++] = data & 0xff;
}


void SockList_AddInt(SockList *sl, uint32 data)
{
    sl->buf[sl->len++]= (data>>24)&0xff;
    sl->buf[sl->len++]= (data>>16)&0xff;
    sl->buf[sl->len++]= (data>>8)&0xff;
    sl->buf[sl->len++] = data & 0xff;
}

void SockList_AddInt64(SockList *sl, uint64 data)
{
    sl->buf[sl->len++]= ( char )( (data>>56)&0xff );
    sl->buf[sl->len++]= ( char )( (data>>48)&0xff );
    sl->buf[sl->len++]= ( char )( (data>>40)&0xff );
    sl->buf[sl->len++]= ( char )( (data>>32)&0xff );

    sl->buf[sl->len++]= ( char )( (data>>24)&0xff );
    sl->buf[sl->len++]= ( char )( (data>>16)&0xff );
    sl->buf[sl->len++]= ( char )( (data>>8)&0xff );
    sl->buf[sl->len++] =( char )(  data & 0xff );
}

/* Basically does the reverse of SockList_AddInt, but on
 * strings instead.  Same for the GetShort, but for 16 bits.
 */
int GetInt_String(unsigned char *data)
{
    return ((data[0]<<24) + (data[1]<<16) + (data[2]<<8) + data[3]);
}

short GetShort_String(unsigned char *data) {
    return ((data[0]<<8)+data[1]);
}

/******************************************************************************
 *
 * Start of read routines.
 *
 ******************************************************************************/

/**
 * This reads from fd and puts the data in sl.  We return true if we think
 * we have a full packet, 0 if we have a partial packet.  The only processing
 * we do is remove the intial size value.  len (As passed) is the size of the
 * buffer allocated in the socklist.  We make the assumption the buffer is
 * at least 2 bytes long.
 */
 
int SockList_ReadPacket(int fd, SockList *sl, int len)
{
    int stat,toread;
    extern int errno;

    /* Sanity check - shouldn't happen */
    if (sl->len < 0) {
        abort();
    }
    /* We already have a partial packet */
    if (sl->len<2) {
#ifdef WIN32 /* ***WIN32 SockList_ReadPacket: change read() to recv() */

        stat=recv(fd, sl->buf + sl->len, 2-sl->len,0);

#else
        do {
                stat=read(fd, sl->buf + sl->len, 2-sl->len);
        } while ((stat==-1) && (errno==EINTR));
#endif
        if (stat<0) {
            /* In non blocking mode, EAGAIN is set when there is no
             * data available.
             */
#ifdef WIN32 /* ***WIN32 SockList_ReadPacket: error handling for win32 */
        if ((stat==-1) && WSAGetLastError() !=WSAEWOULDBLOCK) {
                if(WSAGetLastError() == WSAECONNRESET)
                        LOG(llevDebug,"Connection closed by client\n");
                else
                {
                        LOG(llevDebug,"ReadPacket got error %d, returning 0\n",WSAGetLastError());
                }
                return -1;      /* kick this user! */
            }
#else
        if (errno != EAGAIN && errno !=EWOULDBLOCK) {
                LOG(llevDebug, "ReadPacket got error %s, returning 0\n", strerror_local(errno));
            }
#endif
            return 0;   /*Error */
        }
        if (stat==0) return -1;
        sl->len += stat;
#ifdef CS_LOGSTATS
        cst_tot.ibytes += stat;
        cst_lst.ibytes += stat;
#endif
        if (stat<2) return 0;   /* Still don't have a full packet */
    }
    /* Figure out how much more data we need to read.  Add 2 from the
     * end of this - size header information is not included.
     */
    toread = 2+(sl->buf[0] << 8) + sl->buf[1] - sl->len;
    if ((toread + sl->len) >= len) {
        LOG(llevError,"SockList_ReadPacket: Want to read more bytes than will fit in buffer (%d>=%d).\n",
             toread + sl->len, len);
        /* Quick hack in case for 'oldsocketmode' input.  If we are
         * closing the socket anyways, then reading this extra 100 bytes
         * shouldn't hurt.
         */
#ifdef WIN32 /* ***win32 SockList_ReadPacket: change read() to recv() */
        recv(fd, sl->buf+2, 100, 0);
#else
        read(fd, sl->buf+2, 100);
#endif /* end win32 */

        /* return error so the socket is closed */
        return -1;
    }
    do {
#ifdef WIN32 /* ***win32 SockList_ReadPacket: change read() to recv() */
        stat = recv(fd, sl->buf+ sl->len, toread, 0);
#else
        do {
            stat = read(fd, sl->buf+ sl->len, toread);
        } while ((stat<0) && (errno==EINTR));
#endif
        if (stat<0) {

#ifdef WIN32 /* ***win32 SockList_ReadPacket: change error handling for win32 */
        if ((stat==-1) && WSAGetLastError() !=WSAEWOULDBLOCK) {
                if(WSAGetLastError() == WSAECONNRESET)
                        LOG(llevDebug,"Connection closed by client\n");
                else
                {
                        LOG(llevDebug,"ReadPacket got error %d, returning 0\n",WSAGetLastError());
                }
                return -1;      /* kick this user! */
            }
#else
        if (errno != EAGAIN && errno !=EWOULDBLOCK) {
                LOG(llevDebug, "ReadPacket got error %s, returning 0\n", strerror_local(errno));
            }
#endif
            return 0;   /*Error */
        }
        if (stat==0) return -1;
        sl->len += stat;
#ifdef CS_LOGSTATS
        cst_tot.ibytes += stat;
        cst_lst.ibytes += stat;
#endif
        toread -= stat;
        if (toread==0) return 1;
        if (toread < 0) {
            LOG(llevError,"SockList_ReadPacket: Read more bytes than desired.\n");
            return 1;
        }
    } while (toread>0);
    return 0;
}

/*******************************************************************************
 *
 * Start of write related routines.
 *
 ******************************************************************************/

/**
 * Adds data to a socket buffer for whatever reason.
 *
 * ns is the socket we are adding the data to, buf is the start of the
 * data, and len is the number of bytes to add.
 */

static void add_to_buffer(NewSocket *ns, unsigned char *buf, int len)
{
    int avail, end;

    if ((len+ns->outputbuffer.len)>SOCKETBUFSIZE) {
        LOG(llevDebug,"Socket on fd %d has overrun internal buffer - marking as dead\n",
            ns->fd);
        ns->status = Ns_Dead;
        return;
    }

    /* data + end is where we start putting the new data.  The last byte
     * currently in use is actually data + end -1
     */

    end=ns->outputbuffer.start + ns->outputbuffer.len;
    /* The buffer is already in a wrapped state, so adjust end */
    if (end>=SOCKETBUFSIZE) end-=SOCKETBUFSIZE;
    avail=SOCKETBUFSIZE - end;

    /* We can all fit it behind the current data without wrapping */
    if (avail >=len ) {
        memcpy(ns->outputbuffer.data + end, buf, len);
    }
    else {
        memcpy(ns->outputbuffer.data + end, buf, avail);
        memcpy(ns->outputbuffer.data, buf+avail, len-avail);
    }
    ns->outputbuffer.len += len;
#if 0
    LOG(llevDebug,"Added %d to output buffer, total length now %d, start=%d\n", len,
        ns->outputbuffer.len, ns->outputbuffer.start);
#endif
}

/**
 * Writes data to socket.
 *
 * When the socket is clear to write, and we have backlogged data, this
 * is called to write it out.
 */
void write_socket_buffer(NewSocket *ns)
{
    int amt, max;

    if (ns->outputbuffer.len==0) {
        LOG(llevDebug,"write_socket_buffer called when there is no data, fd=%d\n",
            ns->fd);
        return;
    }

    do {
        max = SOCKETBUFSIZE - ns->outputbuffer.start;
        if (ns->outputbuffer.len<max) max = ns->outputbuffer.len;

#ifdef WIN32 /* ***win32 write_socket_buffer: change write() to send() */
        amt=send(ns->fd, ns->outputbuffer.data + ns->outputbuffer.start, max,0);
#else
        do {
            amt=write(ns->fd, ns->outputbuffer.data + ns->outputbuffer.start, max);
        } while ((amt<0) && (errno==EINTR));
#endif

        if (amt < 0) { /* We got an error */

#ifdef WIN32 /* ***win32 write_socket_buffer: change error handling */
        if (amt == -1 && WSAGetLastError() !=WSAEWOULDBLOCK) {
                LOG(llevError,"New socket write failed (wsb) (%d).\n", WSAGetLastError());
#else
        if (errno !=EWOULDBLOCK) {
                LOG(llevError,"New socket write failed (wsb) (%d: %s).\n",
                    errno, strerror_local(errno));
#endif
                ns->status=Ns_Dead;
                return;
            }
            else { /* EWOULDBLOCK */
                /* can't write it, so store it away. */
                ns->can_write=0;
                return;
            }
        }
        ns->outputbuffer.start += amt;
        /* wrap back to start of buffer */
        if (ns->outputbuffer.start==SOCKETBUFSIZE) ns->outputbuffer.start=0;
        ns->outputbuffer.len -= amt;
#ifdef CS_LOGSTATS
        cst_tot.obytes += amt;
        cst_lst.obytes += amt;
 #endif
    } while (ns->outputbuffer.len>0);
}

/**
 * This writes data to the socket. - It is very low level -
 * all we try and do is write out the data to the socket
 * provided (ns).  buf is the data to write, len is the number
 * of bytes to write.  IT doesn't return anything - rather, it
 * updates the ns structure if we get an  error.
 */
void Write_To_Socket(NewSocket *ns, unsigned char *buf, int len)
{
    int amt=0;
    unsigned char *pos=buf;

    if (ns->status == Ns_Dead || !buf) {
        LOG(llevDebug,"Write_To_Socket called with dead socket\n");
        return;
    }
 
#ifndef __GNU__ /* This caused problems on Hurd */
    if (!ns->can_write) {
        add_to_buffer(ns, buf, len);
        return;
    }
#endif
    /* If we manage to write more than we wanted, take it as a bonus */
    while (len>0) {

#ifdef WIN32 /* ***win32 Write_To_Socket: change write() to send() */
            amt=send(ns->fd, pos, len,0);
#else
        do {
            amt=write(ns->fd, pos, len);
        } while ((amt<0) && (errno==EINTR));
#endif

        if (amt < 0) { /* We got an error */
#ifdef WIN32 /* ***win32 Write_To_Socket: change error handling */
        if (amt == -1 && WSAGetLastError() !=WSAEWOULDBLOCK) {
                LOG(llevError,"New socket write failed WTS (%d).\n",WSAGetLastError());
#else
        if (errno !=EWOULDBLOCK) {
                LOG(llevError,"New socket write failed WTS (%d: %s).\n", /* ---WIN32 */
                    errno, strerror_local(errno));
#endif
                ns->status=Ns_Dead;
                return;
            }
            else { /* EWOULDBLOCK */
                /* can't write it, so store it away. */
                add_to_buffer(ns, pos, len);
                ns->can_write=0;
                return;
            }
        }
        /* amt gets set to 0 above in blocking code, so we do this as
         * an else if to make sure we don't reprocess it.
         */
        else if (amt==0) {
            LOG(llevError,"Write_To_Socket: No data written out.\n");
        }
        len -= amt;
        pos += amt;
#ifdef CS_LOGSTATS
        cst_tot.obytes += amt;
        cst_lst.obytes += amt;
 #endif
    }
}


/**
 * Takes a string of data, and writes it out to the socket. A very handy
 * shortcut function.
 */
void cs_write_string(NewSocket *ns, const char *buf, int len)
{
    SockList sl;

    sl.len = len;
    sl.buf = (unsigned char*)buf;
    Send_With_Handling(ns, &sl);
}


/**
 * Calls Write_To_Socket to send data to the client.
 *
 * The only difference in this function is that we take a SockList
 *, and we prepend the length information.
 */
void Send_With_Handling(NewSocket *ns,SockList  *msg)
{
    unsigned char sbuf[4];

    if (ns->status == Ns_Dead || !msg)
        return;

    if (msg->len >= MAXSOCKBUF) {
        LOG(llevError,"Trying to send a buffer beyond properly size, len =%d\n",
            msg->len);
        /* Almost certainly we've overflowed a buffer, so quite now to make
         * it easier to debug.
         */
        abort();
    }
    sbuf[0] = ((uint32)(msg->len) >> 8) & 0xFF;
    sbuf[1] = ((uint32)(msg->len)) & 0xFF;
    if (ns->status != Ns_Old) 
        Write_To_Socket(ns, sbuf, 2);
    Write_To_Socket(ns, msg->buf, msg->len);
}

/**
 * Takes a string of data, and writes it out to the socket. A very handy
 * shortcut function.
 */
void Write_String_To_Socket(NewSocket *ns, char *buf, int len)
{
    SockList sl;

    sl.len = len;
    sl.buf = (uint8*)buf;
    Send_With_Handling(ns, &sl);
}


/******************************************************************************
 *
 * statistics logging functions.
 *
 ******************************************************************************/

#ifdef CS_LOGSTATS
/* cst_tot is for the life of the server, cst_last is for the last series of
 * stats
 */
CS_Stats cst_tot, cst_lst;

/**
 * Writes out the gathered stats.  We clear cst_lst.
 */
void write_cs_stats(void)
{
    time_t now=time(NULL);

    /* If no connections recently, don't both to log anything */
    if (cst_lst.ibytes==0 && cst_lst.obytes==0) return;

    /* CSSTAT is put in so scripts can easily find the line */
    LOG(llevInfo, "CSSTAT: %.16s tot %d %d %d %d inc %d %d %d %d\n",
        ctime(&now), cst_tot.ibytes, cst_tot.obytes, cst_tot.max_conn,
        now - cst_tot.time_start, cst_lst.ibytes, cst_lst.obytes,
        cst_lst.max_conn, now - cst_lst.time_start);
    cst_lst.ibytes=0;
    cst_lst.obytes=0;
    cst_lst.max_conn=socket_info.nconns;
    cst_lst.time_start=now;
}
#endif
Revision:	1.3
Committed:	Fri Jun 2 00:49:03 2006 UTC (20 years, 5 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.2:	+20 -0 lines
Log Message:	on linux, check wether the data sent/ack received difference grows larger than 20s, then disconnect. this should be a reliable way to detect dead connections without adding any bandwidth overhead
#	User	Rev	Content
1	root	1.1
2			/*
3			* static char *rcsid_sockets_c =
4	root	1.2	* "$Id$";
5	root	1.1	*/
6
7			/*
8			CrossFire, A Multiplayer game for X-windows
9
10			Copyright (C) 1992 Frank Tore Johansen
11
12			This program is free software; you can redistribute it and/or modify
13			it under the terms of the GNU General Public License as published by
14			the Free Software Foundation; either version 2 of the License, or
15			(at your option) any later version.
16
17			This program is distributed in the hope that it will be useful,
18			but WITHOUT ANY WARRANTY; without even the implied warranty of
19			MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20			GNU General Public License for more details.
21
22			You should have received a copy of the GNU General Public License
23			along with this program; if not, write to the Free Software
24			Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25
26			The author can be reached via e-mail to mark@pyramid.com
27			*/
28
29			/**
30			* \file
31			* Low-level socket-related functions.
32			*
33			* \date 2003-12-02
34			*
35			* Contains some base functions that both the client and server
36			* can use. As such, depending what we are being compiled for will
37			* determine what we can include. the client is designed have
38			* CFCLIENT defined as part of its compile flags.
39			*/
40
41			#include <global.h>
42			#include <newclient.h>
43			#include <sproto.h>
44
45	root	1.2	#ifdef __linux__
46			# include <sys/types.h>
47			# include <sys/socket.h>
48			# include <netinet/in.h>
49	root	1.3	# define TCP_HZ 1000 // sorry...
50	root	1.2	# include <netinet/tcp.h>
51			#endif
52
53	root	1.3	// use a really low timeout, as it doesn't cost any bandwidth, and you can
54			// easily die in 20 seconds... (actually, 20s after the last data was sent
55			#define SOCKET_TIMEOUT 20
56
57	root	1.2	void Socket_Flush (NewSocket *ns)
58			{
59			#ifdef __linux__
60			int val;
61			val = 0; setsockopt (ns->fd, IPPROTO_TCP, TCP_CORK, &val, sizeof (val));
62			val = 1; setsockopt (ns->fd, IPPROTO_TCP, TCP_CORK, &val, sizeof (val));
63	root	1.3
64			// check time of last ack, and, if too old, kill connection
65			struct tcp_info tcpi;
66			socklen_t len = sizeof (tcpi);
67			if (!getsockopt (ns->fd, IPPROTO_TCP, TCP_INFO, &tcpi, &len) && len == sizeof (tcpi))
68			{
69			unsigned int diff = tcpi.tcpi_last_ack_recv - tcpi.tcpi_last_data_sent;
70
71			if (SOCKET_TIMEOUT * TCP_HZ < diff && diff < 0x80000000UL)
72			{
73			LOG (llevDebug, "Connection on fd %d closed due to ack timeout (%u/%u)\n", ns->fd,
74			(unsigned)tcpi.tcpi_last_ack_recv, (unsigned)tcpi.tcpi_last_data_sent);
75			ns->status = Ns_Dead;
76			}
77			}
78	root	1.2	#endif
79			}
80
81	root	1.1	/***********************************************************************
82			*
83			* SockList functions/utilities
84			*
85			**********************************************************************/
86
87			void SockList_Init(SockList *sl)
88			{
89			sl->len=0;
90			sl->buf=NULL;
91			}
92
93			void SockList_AddChar(SockList *sl, char c)
94			{
95			sl->buf[sl->len]=c;
96			sl->len++;
97			}
98
99			void SockList_AddShort(SockList *sl, uint16 data)
100			{
101			sl->buf[sl->len++]= (data>>8)&0xff;
102			sl->buf[sl->len++] = data & 0xff;
103			}
104
105
106			void SockList_AddInt(SockList *sl, uint32 data)
107			{
108			sl->buf[sl->len++]= (data>>24)&0xff;
109			sl->buf[sl->len++]= (data>>16)&0xff;
110			sl->buf[sl->len++]= (data>>8)&0xff;
111			sl->buf[sl->len++] = data & 0xff;
112			}
113
114			void SockList_AddInt64(SockList *sl, uint64 data)
115			{
116			sl->buf[sl->len++]= ( char )( (data>>56)&0xff );
117			sl->buf[sl->len++]= ( char )( (data>>48)&0xff );
118			sl->buf[sl->len++]= ( char )( (data>>40)&0xff );
119			sl->buf[sl->len++]= ( char )( (data>>32)&0xff );
120
121			sl->buf[sl->len++]= ( char )( (data>>24)&0xff );
122			sl->buf[sl->len++]= ( char )( (data>>16)&0xff );
123			sl->buf[sl->len++]= ( char )( (data>>8)&0xff );
124			sl->buf[sl->len++] =( char )( data & 0xff );
125			}
126
127			/* Basically does the reverse of SockList_AddInt, but on
128			* strings instead. Same for the GetShort, but for 16 bits.
129			*/
130			int GetInt_String(unsigned char *data)
131			{
132			return ((data[0]<<24) + (data[1]<<16) + (data[2]<<8) + data[3]);
133			}
134
135			short GetShort_String(unsigned char *data) {
136			return ((data[0]<<8)+data[1]);
137			}
138
139			/******************************************************************************
140			*
141			* Start of read routines.
142			*
143			******************************************************************************/
144
145			/**
146			* This reads from fd and puts the data in sl. We return true if we think
147			* we have a full packet, 0 if we have a partial packet. The only processing
148			* we do is remove the intial size value. len (As passed) is the size of the
149			* buffer allocated in the socklist. We make the assumption the buffer is
150			* at least 2 bytes long.
151			*/
152
153			int SockList_ReadPacket(int fd, SockList *sl, int len)
154			{
155			int stat,toread;
156			extern int errno;
157
158			/* Sanity check - shouldn't happen */
159			if (sl->len < 0) {
160			abort();
161			}
162			/* We already have a partial packet */
163			if (sl->len<2) {
164			#ifdef WIN32 /* **WIN32 SockList_ReadPacket: change read() to recv() /
165
166			stat=recv(fd, sl->buf + sl->len, 2-sl->len,0);
167
168			#else
169			do {
170			stat=read(fd, sl->buf + sl->len, 2-sl->len);
171			} while ((stat==-1) && (errno==EINTR));
172			#endif
173			if (stat<0) {
174			/* In non blocking mode, EAGAIN is set when there is no
175			* data available.
176			*/
177			#ifdef WIN32 /* **WIN32 SockList_ReadPacket: error handling for win32 /
178			if ((stat==-1) && WSAGetLastError() !=WSAEWOULDBLOCK) {
179			if(WSAGetLastError() == WSAECONNRESET)
180			LOG(llevDebug,"Connection closed by client\n");
181			else
182			{
183			LOG(llevDebug,"ReadPacket got error %d, returning 0\n",WSAGetLastError());
184			}
185			return -1; /* kick this user! */
186			}
187			#else
188			if (errno != EAGAIN && errno !=EWOULDBLOCK) {
189			LOG(llevDebug, "ReadPacket got error %s, returning 0\n", strerror_local(errno));
190			}
191			#endif
192			return 0; /Error /
193			}
194			if (stat==0) return -1;
195			sl->len += stat;
196			#ifdef CS_LOGSTATS
197			cst_tot.ibytes += stat;
198			cst_lst.ibytes += stat;
199			#endif
200			if (stat<2) return 0; /* Still don't have a full packet */
201			}
202			/* Figure out how much more data we need to read. Add 2 from the
203			* end of this - size header information is not included.
204			*/
205			toread = 2+(sl->buf[0] << 8) + sl->buf[1] - sl->len;
206			if ((toread + sl->len) >= len) {
207			LOG(llevError,"SockList_ReadPacket: Want to read more bytes than will fit in buffer (%d>=%d).\n",
208			toread + sl->len, len);
209			/* Quick hack in case for 'oldsocketmode' input. If we are
210			* closing the socket anyways, then reading this extra 100 bytes
211			* shouldn't hurt.
212			*/
213			#ifdef WIN32 /* **win32 SockList_ReadPacket: change read() to recv() /
214			recv(fd, sl->buf+2, 100, 0);
215			#else
216			read(fd, sl->buf+2, 100);
217			#endif /* end win32 */
218
219			/* return error so the socket is closed */
220			return -1;
221			}
222			do {
223			#ifdef WIN32 /* **win32 SockList_ReadPacket: change read() to recv() /
224			stat = recv(fd, sl->buf+ sl->len, toread, 0);
225			#else
226			do {
227			stat = read(fd, sl->buf+ sl->len, toread);
228			} while ((stat<0) && (errno==EINTR));
229			#endif
230			if (stat<0) {
231
232			#ifdef WIN32 /* **win32 SockList_ReadPacket: change error handling for win32 /
233			if ((stat==-1) && WSAGetLastError() !=WSAEWOULDBLOCK) {
234			if(WSAGetLastError() == WSAECONNRESET)
235			LOG(llevDebug,"Connection closed by client\n");
236			else
237			{
238			LOG(llevDebug,"ReadPacket got error %d, returning 0\n",WSAGetLastError());
239			}
240			return -1; /* kick this user! */
241			}
242			#else
243			if (errno != EAGAIN && errno !=EWOULDBLOCK) {
244			LOG(llevDebug, "ReadPacket got error %s, returning 0\n", strerror_local(errno));
245			}
246			#endif
247			return 0; /Error /
248			}
249			if (stat==0) return -1;
250			sl->len += stat;
251			#ifdef CS_LOGSTATS
252			cst_tot.ibytes += stat;
253			cst_lst.ibytes += stat;
254			#endif
255			toread -= stat;
256			if (toread==0) return 1;
257			if (toread < 0) {
258			LOG(llevError,"SockList_ReadPacket: Read more bytes than desired.\n");
259			return 1;
260			}
261			} while (toread>0);
262			return 0;
263			}
264
265			/*******************************************************************************
266			*
267			* Start of write related routines.
268			*
269			******************************************************************************/
270
271			/**
272			* Adds data to a socket buffer for whatever reason.
273			*
274			* ns is the socket we are adding the data to, buf is the start of the
275			* data, and len is the number of bytes to add.
276			*/
277
278			static void add_to_buffer(NewSocket ns, unsigned char buf, int len)
279			{
280			int avail, end;
281
282			if ((len+ns->outputbuffer.len)>SOCKETBUFSIZE) {
283			LOG(llevDebug,"Socket on fd %d has overrun internal buffer - marking as dead\n",
284			ns->fd);
285			ns->status = Ns_Dead;
286			return;
287			}
288
289			/* data + end is where we start putting the new data. The last byte
290			* currently in use is actually data + end -1
291			*/
292
293			end=ns->outputbuffer.start + ns->outputbuffer.len;
294			/* The buffer is already in a wrapped state, so adjust end */
295			if (end>=SOCKETBUFSIZE) end-=SOCKETBUFSIZE;
296			avail=SOCKETBUFSIZE - end;
297
298			/* We can all fit it behind the current data without wrapping */
299			if (avail >=len ) {
300			memcpy(ns->outputbuffer.data + end, buf, len);
301			}
302			else {
303			memcpy(ns->outputbuffer.data + end, buf, avail);
304			memcpy(ns->outputbuffer.data, buf+avail, len-avail);
305			}
306			ns->outputbuffer.len += len;
307			#if 0
308			LOG(llevDebug,"Added %d to output buffer, total length now %d, start=%d\n", len,
309			ns->outputbuffer.len, ns->outputbuffer.start);
310			#endif
311			}
312
313			/**
314			* Writes data to socket.
315			*
316			* When the socket is clear to write, and we have backlogged data, this
317			* is called to write it out.
318			*/
319			void write_socket_buffer(NewSocket *ns)
320			{
321			int amt, max;
322
323			if (ns->outputbuffer.len==0) {
324			LOG(llevDebug,"write_socket_buffer called when there is no data, fd=%d\n",
325			ns->fd);
326			return;
327			}
328
329			do {
330			max = SOCKETBUFSIZE - ns->outputbuffer.start;
331			if (ns->outputbuffer.len<max) max = ns->outputbuffer.len;
332
333			#ifdef WIN32 /* **win32 write_socket_buffer: change write() to send() /
334			amt=send(ns->fd, ns->outputbuffer.data + ns->outputbuffer.start, max,0);
335			#else
336			do {
337			amt=write(ns->fd, ns->outputbuffer.data + ns->outputbuffer.start, max);
338			} while ((amt<0) && (errno==EINTR));
339			#endif
340
341			if (amt < 0) { /* We got an error */
342
343			#ifdef WIN32 /* **win32 write_socket_buffer: change error handling /
344			if (amt == -1 && WSAGetLastError() !=WSAEWOULDBLOCK) {
345			LOG(llevError,"New socket write failed (wsb) (%d).\n", WSAGetLastError());
346			#else
347			if (errno !=EWOULDBLOCK) {
348			LOG(llevError,"New socket write failed (wsb) (%d: %s).\n",
349			errno, strerror_local(errno));
350			#endif
351			ns->status=Ns_Dead;
352			return;
353			}
354			else { /* EWOULDBLOCK */
355			/* can't write it, so store it away. */
356			ns->can_write=0;
357			return;
358			}
359			}
360			ns->outputbuffer.start += amt;
361			/* wrap back to start of buffer */
362			if (ns->outputbuffer.start==SOCKETBUFSIZE) ns->outputbuffer.start=0;
363			ns->outputbuffer.len -= amt;
364			#ifdef CS_LOGSTATS
365			cst_tot.obytes += amt;
366			cst_lst.obytes += amt;
367			#endif
368			} while (ns->outputbuffer.len>0);
369			}
370
371			/**
372			* This writes data to the socket. - It is very low level -
373			* all we try and do is write out the data to the socket
374			* provided (ns). buf is the data to write, len is the number
375			* of bytes to write. IT doesn't return anything - rather, it
376			* updates the ns structure if we get an error.
377			*/
378			void Write_To_Socket(NewSocket ns, unsigned char buf, int len)
379			{
380			int amt=0;
381			unsigned char *pos=buf;
382
383			if (ns->status == Ns_Dead \|\| !buf) {
384			LOG(llevDebug,"Write_To_Socket called with dead socket\n");
385			return;
386			}
387
388			#ifndef __GNU__ /* This caused problems on Hurd */
389			if (!ns->can_write) {
390			add_to_buffer(ns, buf, len);
391			return;
392			}
393			#endif
394			/* If we manage to write more than we wanted, take it as a bonus */
395			while (len>0) {
396
397			#ifdef WIN32 /* **win32 Write_To_Socket: change write() to send() /
398			amt=send(ns->fd, pos, len,0);
399			#else
400			do {
401			amt=write(ns->fd, pos, len);
402			} while ((amt<0) && (errno==EINTR));
403			#endif
404
405			if (amt < 0) { /* We got an error */
406			#ifdef WIN32 /* **win32 Write_To_Socket: change error handling /
407			if (amt == -1 && WSAGetLastError() !=WSAEWOULDBLOCK) {
408			LOG(llevError,"New socket write failed WTS (%d).\n",WSAGetLastError());
409			#else
410			if (errno !=EWOULDBLOCK) {
411			LOG(llevError,"New socket write failed WTS (%d: %s).\n", /* ---WIN32 */
412			errno, strerror_local(errno));
413			#endif
414			ns->status=Ns_Dead;
415			return;
416			}
417			else { /* EWOULDBLOCK */
418			/* can't write it, so store it away. */
419			add_to_buffer(ns, pos, len);
420			ns->can_write=0;
421			return;
422			}
423			}
424			/* amt gets set to 0 above in blocking code, so we do this as
425			* an else if to make sure we don't reprocess it.
426			*/
427			else if (amt==0) {
428			LOG(llevError,"Write_To_Socket: No data written out.\n");
429			}
430			len -= amt;
431			pos += amt;
432			#ifdef CS_LOGSTATS
433			cst_tot.obytes += amt;
434			cst_lst.obytes += amt;
435			#endif
436			}
437			}
438
439
440			/**
441			* Takes a string of data, and writes it out to the socket. A very handy
442			* shortcut function.
443			*/
444			void cs_write_string(NewSocket ns, const char buf, int len)
445			{
446			SockList sl;
447
448			sl.len = len;
449			sl.buf = (unsigned char*)buf;
450			Send_With_Handling(ns, &sl);
451			}
452
453
454			/**
455			* Calls Write_To_Socket to send data to the client.
456			*
457			* The only difference in this function is that we take a SockList
458			*, and we prepend the length information.
459			*/
460			void Send_With_Handling(NewSocket ns,SockList msg)
461			{
462			unsigned char sbuf[4];
463
464			if (ns->status == Ns_Dead \|\| !msg)
465			return;
466
467			if (msg->len >= MAXSOCKBUF) {
468			LOG(llevError,"Trying to send a buffer beyond properly size, len =%d\n",
469			msg->len);
470			/* Almost certainly we've overflowed a buffer, so quite now to make
471			* it easier to debug.
472			*/
473			abort();
474			}
475			sbuf[0] = ((uint32)(msg->len) >> 8) & 0xFF;
476			sbuf[1] = ((uint32)(msg->len)) & 0xFF;
477			if (ns->status != Ns_Old)
478			Write_To_Socket(ns, sbuf, 2);
479			Write_To_Socket(ns, msg->buf, msg->len);
480			}
481
482			/**
483			* Takes a string of data, and writes it out to the socket. A very handy
484			* shortcut function.
485			*/
486			void Write_String_To_Socket(NewSocket ns, char buf, int len)
487			{
488			SockList sl;
489
490			sl.len = len;
491			sl.buf = (uint8*)buf;
492			Send_With_Handling(ns, &sl);
493			}
494
495
496			/******************************************************************************
497			*
498			* statistics logging functions.
499			*
500			******************************************************************************/
501
502			#ifdef CS_LOGSTATS
503			/* cst_tot is for the life of the server, cst_last is for the last series of
504			* stats
505			*/
506			CS_Stats cst_tot, cst_lst;
507
508			/**
509			* Writes out the gathered stats. We clear cst_lst.
510			*/
511			void write_cs_stats(void)
512			{
513			time_t now=time(NULL);
514
515			/* If no connections recently, don't both to log anything */
516			if (cst_lst.ibytes==0 && cst_lst.obytes==0) return;
517
518			/* CSSTAT is put in so scripts can easily find the line */
519			LOG(llevInfo, "CSSTAT: %.16s tot %d %d %d %d inc %d %d %d %d\n",
520			ctime(&now), cst_tot.ibytes, cst_tot.obytes, cst_tot.max_conn,
521			now - cst_tot.time_start, cst_lst.ibytes, cst_lst.obytes,
522			cst_lst.max_conn, now - cst_lst.time_start);
523			cst_lst.ibytes=0;
524			cst_lst.obytes=0;
525			cst_lst.max_conn=socket_info.nconns;
526			cst_lst.time_start=now;
527			}
528			#endif