/*
 * $Id: logfile_mod_udp.c,v 1.7 2008/06/04 20:12:58 hno Exp $
 *
 * DEBUG: section 50    Log file handling
 * AUTHOR: Adrian Chadd
 *
 * SQUID Web Proxy Cache          http://www.squid-cache.org/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from
 *  the Internet community; see the CONTRIBUTORS file for full
 *  details.   Many organizations have provided support for Squid's
 *  development; see the SPONSORS file for full details.  Squid is
 *  Copyrighted (C) 2001 by the Regents of the University of
 *  California; see the COPYRIGHT file for full details.  Squid
 *  incorporates software developed and/or copyrighted by other
 *  sources; see the CREDITS file for full details.
 *
 *  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., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 */

#include "squid.h"
#include "logfile_mod_udp.h"

/*
 * This logfile udp helper is mostly inspired by a patch by Tim Starling
 * from Wikimedia.
 *
 * It doesn't do any UDP buffering - it'd be quite a bit of work for
 * something which the kernel could be doing for you!
 */

typedef struct {
    int fd;
    char *buf;
    int bufsz;
    int offset;
} l_udp_t;

static void
logfile_mod_udp_write(Logfile * lf, const char *buf, size_t len)
{
    l_udp_t *ll = (l_udp_t *) lf->data;
    ssize_t s;
    s = write(ll->fd, (char const *) buf, len);
    fd_bytes(ll->fd, s, FD_WRITE);
#if 0
    if (s < 0) {
	debug(1, 1) ("logfile (udp): got errno %d (%s)\n", errno, xstrerror());
    }
    if (s != len) {
	debug(1, 1) ("logfile (udp): len %d, wrote %d\n", len, s);
    }
#endif

    /* We don't worry about network errors for now */
}

static void
logfile_mod_udp_flush(Logfile * lf)
{
    l_udp_t *ll = (l_udp_t *) lf->data;
    if (0 == ll->offset)
	return;
    logfile_mod_udp_write(lf, ll->buf, (size_t) ll->offset);
    ll->offset = 0;
}


static void
logfile_mod_udp_writeline(Logfile * lf, const char *buf, size_t len)
{
    l_udp_t *ll = (l_udp_t *) lf->data;

    if (0 == ll->bufsz) {
	/* buffering disabled */
	logfile_mod_udp_write(lf, buf, len);
	return;
    }
    if (ll->offset > 0 && ll->offset + len + 4 > ll->bufsz)
	logfile_mod_udp_flush(lf);

    if (len > ll->bufsz) {
	/* too big to fit in buffer */
	logfile_mod_udp_write(lf, buf, len);
	return;
    }
    /* buffer it */
    xmemcpy(ll->buf + ll->offset, buf, len);

    ll->offset += len;

    assert(ll->offset >= 0);

    assert((size_t) ll->offset <= ll->bufsz);
}

static void
logfile_mod_udp_linestart(Logfile * lf)
{
}

static void
logfile_mod_udp_lineend(Logfile * lf)
{
}

static void
logfile_mod_udp_rotate(Logfile * lf)
{
    return;
}

static void
logfile_mod_udp_close(Logfile * lf)
{
    l_udp_t *ll = (l_udp_t *) lf->data;
    lf->f_flush(lf);

    if (ll->fd >= 0)
	file_close(ll->fd);

    if (ll->buf)
	xfree(ll->buf);

    xfree(lf->data);
    lf->data = NULL;
}



/*
 * This code expects the path to be syslog:<priority>
 */
int
logfile_mod_udp_open(Logfile * lf, const char *path, size_t bufsz, int fatal_flag)
{
    l_udp_t *ll;
    struct sockaddr_in addr;
    char *strAddr;

    lf->f_close = logfile_mod_udp_close;
    lf->f_linewrite = logfile_mod_udp_writeline;
    lf->f_linestart = logfile_mod_udp_linestart;
    lf->f_lineend = logfile_mod_udp_lineend;
    lf->f_flush = logfile_mod_udp_flush;
    lf->f_rotate = logfile_mod_udp_rotate;

    ll = xcalloc(1, sizeof(*ll));
    lf->data = ll;

    if (strncmp(path, "//", 2) == 0) {
	path += 2;
    }
    strAddr = xstrdup(path);
    if (!parse_sockaddr(strAddr, &addr)) {
	if (lf->flags.fatal) {
	    fatalf("Invalid UDP logging address '%s'\n", lf->path);
	} else {
	    debug(50, 1) ("Invalid UDP logging address '%s'\n", lf->path);
	    safe_free(strAddr);
	    return FALSE;
	}
    }
    safe_free(strAddr);

    ll->fd = comm_open(SOCK_DGRAM,
	IPPROTO_UDP,
	no_addr,
	0,
	COMM_NONBLOCKING,
	"UDP log socket");
    if (ll->fd < 0) {
	if (lf->flags.fatal) {
	    fatalf("Unable to open UDP socket for logging\n");
	} else {
	    debug(50, 1) ("Unable to open UDP socket for logging\n");
	    return FALSE;
	}
    }
    if (comm_connect_addr(ll->fd, &addr)) {
	if (lf->flags.fatal) {
	    fatalf("Unable to connect to %s for UDP log: %s\n", lf->path, xstrerror());
	} else {
	    debug(50, 1) ("Unable to connect to %s for UDP log: %s\n", lf->path, xstrerror());
	    return FALSE;
	}
    }
    if (ll->fd == -1) {
	if (ENOENT == errno && fatal_flag) {
	    fatalf("Cannot open '%s' because\n"
		"\tthe parent directory does not exist.\n"
		"\tPlease create the directory.\n", path);
	} else if (EACCES == errno && fatal_flag) {
	    fatalf("Cannot open '%s' for writing.\n"
		"\tThe parent directory must be writeable by the\n"
		"\tuser '%s', which is the cache_effective_user\n"
		"\tset in squid.conf.", path, Config.effectiveUser);
	} else {
	    debug(50, 1) ("logfileOpen (stdio): %s: %s\n", path, xstrerror());
	    return 0;
	}
    }
    /* Force buffer size to something roughly fitting inside an MTU */
    /*
     * XXX note the receive side needs to receive the whole packet at once;
     * applications like netcat have a small default receive buffer and will
     * truncate!
     */
    bufsz = 1400;
    if (bufsz > 0) {
	ll->buf = (char *) xmalloc(bufsz);
	ll->bufsz = bufsz;
    }
    return 1;
}