/*
**  L2 - OSSP Logging Library
**  Copyright (c) 2001 The OSSP Project (http://www.ossp.org/)
**  Copyright (c) 2001 Cable & Wireless Deutschland (http://www.cw.com/de/)
**
**  This file is part of OSSP L2, a flexible logging library which
**  can be found at http://www.ossp.org/pkg/l2/.
**
**  Permission to use, copy, modify, and distribute this software for
**  any purpose with or without fee is hereby granted, provided that
**  the above copyright notice and this permission notice appear in all
**  copies.
**
**  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
**  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
**  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
**  IN NO EVENT SHALL THE AUTHORS AND COPYRIGHT HOLDERS AND THEIR
**  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
**  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
**  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
**  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
**  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
**  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
**  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
**  SUCH DAMAGE.
**
**  l2_ch_socket.c: socket channel implementation
*/

#include <unistd.h>
#include <errno.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include "l2.h"
#include "l2_p.h"

#if defined(HAVE_INET_PTON)
#define l2_inet_pton inet_pton
#elif defined(HAVE_INET_ATON)

/******************************************************************
IPv4 source used from Unix Network Programming by Richard STEVENS
 ******************************************************************/
static int l2_inet_pton(int iFamily, const char *pszAddress, void *pvMemref)
{
    int             i             = 0;
    struct in_addr  IP4Addr;
    struct in6_addr IP6Addr;
    const char      *pszIndex     = NULL;    /* To index IPv6 validity */
    char            *pszNextfield = "";      /* For IPv6 address trans */

    if (iFamily == AF_INET) {
        if (inet_aton(pszAddress, &IP4Addr)) {
            memcpy(pvMemref, &IP4Addr, sizeof(struct in_addr));
            return 1; /* Success */
        }
        return 0;
    }
    else if (iFamily == AF_INET6) { /* Translate IPv6 addresses               */
        pszIndex = pszAddress;      /* Initialize, verify in loop             */
        for (i = 0; (i < 8) && pszNextfield; i++) { /* Iterate through fields */
            IP6Addr.__u6_addr.__u6_addr16[i] =\
                ntohs((u_int16_t)strtol(pszIndex, &pszNextfield, 16));
            pszIndex = pszNextfield + 1;
        }

        if ((i != 8) || (*pszNextfield))
            return 0;
        else { /* Success */
            memcpy(pvMemref, &IP6Addr, sizeof(struct in6_addr));
            return 1;
        }
    }
    else {    /* User converting from an address family that we don't support */
        errno = EAFNOSUPPORT;
        return -1;
    }
}
#else
#error "neither inet_pton nor inet_aton available"
#endif

/* declare private channel configuration */
typedef struct {
    char *pszHost;           /* IP Address or name of host to connect to    */
    int  iFamily;            /* IP version to use, AF_INET4 or AF_INET6     */
    int  iProto;             /* Protocol to use, IPPROTO_TCP or IPPROTO_UDP */
    int  iPort;              /* TCP Port to connect to                      */
    int  iSocket;            /* Socket descriptor used during writing       */
} l2_ch_socket_t;

/* create channel */
static l2_result_t hook_create(l2_context_t *ctx, l2_channel_t *ch)
{
    l2_ch_socket_t *cfg = NULL;

    /* allocate private channel configuration */
    if ((cfg = (l2_ch_socket_t *)malloc(sizeof(l2_ch_socket_t))) == NULL)
        return L2_ERR_MEM;

    /* initialize configuration with reasonable defaults */
    cfg->pszHost   = NULL;
    cfg->iFamily   = -1;
    cfg->iProto    = -1;
    cfg->iPort     = 0;
    cfg->iSocket   = -1;

    /* link private channel configuration into channel context */
    ctx->vp = cfg;

    return L2_OK;
}

/* configure channel */
static l2_result_t hook_configure(l2_context_t *ctx, l2_channel_t *ch, const char *fmt, va_list ap)
{
    l2_ch_socket_t *cfg = (l2_ch_socket_t *)ctx->vp;
    l2_param_t pa[5];
    l2_result_t rv;

    /* feed and call generic parameter parsing engine */
    L2_PARAM_SET(pa[0], ipversion, INT,     &cfg->iFamily);
    L2_PARAM_SET(pa[1], protocol,  INT,     &cfg->iProto );
    L2_PARAM_SET(pa[2], host,      CHARPTR, &cfg->pszHost);
    L2_PARAM_SET(pa[3], port,      INT,     &cfg->iPort  );
    L2_PARAM_END(pa[4]);
    rv = l2_util_setparams(pa, fmt, ap);

    return rv;
}

/* open channel */
static l2_result_t hook_open(l2_context_t *ctx, l2_channel_t *ch)
{
    l2_ch_socket_t      *cfg = (l2_ch_socket_t *)ctx->vp;
    struct hostent      *pHostentry;
    struct sockaddr_in  IP4Localsock, IP4Sockaddr;
    struct sockaddr_in6 IP6Localsock, IP6Sockaddr;

    /* make sure a target is configured */
    if (cfg->pszHost == NULL)
        return L2_ERR_USE;

    /* open channel socket */
    if (cfg->iFamily == AF_INET) { /* IPv4 */
        /* initialize address structures */
        memset(&IP4Localsock, 0, sizeof(IP4Localsock));
        memset(&IP4Sockaddr,  0, sizeof(IP4Sockaddr));

        /* resolve host numerically */
        if (l2_inet_pton(AF_INET, cfg->pszHost, &IP4Sockaddr.sin_addr.s_addr) == 1) {
            IP4Sockaddr.sin_family = AF_INET;
            IP4Sockaddr.sin_port   = htons(cfg->iPort);
        }
        /* resolve host nominally */
        else if ((pHostentry = gethostbyname(cfg->pszHost)) != NULL) {
            if (pHostentry->h_addrtype == AF_INET) {
                IP4Sockaddr.sin_family = AF_INET;
                IP4Sockaddr.sin_port   = htons(cfg->iPort);
                memcpy(&IP4Sockaddr.sin_addr.s_addr, pHostentry->h_addr_list[0],
                       sizeof(IP4Sockaddr.sin_addr.s_addr));
            }
            else
                return L2_ERR_USE; /* what?? we specify IPv4 when it is not? */
        }
        else /* host string was not parsable for some reason */
            return L2_ERR_SYS;

        if (cfg->iProto == IPPROTO_TCP) {        /* with TCP we must connect */
            if ((cfg->iSocket = socket(PF_INET, SOCK_STREAM, cfg->iProto)) == -1)
                return L2_ERR_SYS;

            /* if we have a socket, then bind ourselves to any port number   */
            IP4Localsock.sin_family      = AF_INET;
            IP4Localsock.sin_addr.s_addr = htonl(INADDR_ANY);
            IP4Localsock.sin_port        = htons(0);

            if (bind(cfg->iSocket, (struct sockaddr *)&IP4Localsock,\
                sizeof(IP4Localsock))) {
                return L2_ERR_SYS;
            }

            if (connect(cfg->iSocket, (struct sockaddr *)&IP4Sockaddr,
                sizeof(IP4Sockaddr))) {
                close(cfg->iSocket);
                return L2_ERR_SYS;
            }
        }
        else if (cfg->iProto == IPPROTO_UDP) { /* with UDP we do not connect  */
            if ((cfg->iSocket = socket(PF_INET, SOCK_DGRAM, cfg->iProto)) == -1)
                return L2_ERR_SYS;

            /* if we have a socket, then bind ourselves to any port number   */
            IP4Localsock.sin_family      = AF_INET;
            IP4Localsock.sin_addr.s_addr = htonl(INADDR_ANY);
            IP4Localsock.sin_port        = htons(0);

            if (bind(cfg->iSocket, (struct sockaddr *)&IP4Localsock,\
                sizeof(IP4Localsock))) {
                return L2_ERR_SYS;
            }
        }

        return L2_OK;
    }
    else if (cfg->iFamily == AF_INET6) { /* IPv6 */
        /* initialize address structures */
        memset(&IP6Localsock, 0, sizeof(IP6Localsock));
        memset(&IP6Sockaddr,  0, sizeof(IP6Sockaddr));

        /* resolve host numerically */
        if (l2_inet_pton(AF_INET6, cfg->pszHost, &IP6Sockaddr.sin6_addr.s6_addr) == 1) {
            IP6Sockaddr.sin6_family = AF_INET6;
            IP6Sockaddr.sin6_port   = htons(cfg->iPort);
        }
        /* resolve host nominally */
        else if ((pHostentry = gethostbyname(cfg->pszHost)) != NULL) {
            if (pHostentry->h_addrtype == AF_INET6) {
                IP6Sockaddr.sin6_family = AF_INET6;
                IP6Sockaddr.sin6_port   = htons(cfg->iPort);
                memcpy(&IP6Sockaddr.sin6_addr.__u6_addr, pHostentry->h_addr_list[0],\
                    sizeof(IP6Sockaddr.sin6_addr.__u6_addr));
            }
            else
                return L2_ERR_USE; /* what?? we specify IPv6 when it is not?  */
        }
        else                  /* host string was not parsable for some reason */
            return L2_ERR_SYS;

        if (cfg->iProto == IPPROTO_TCP) {         /* with TCP we must connect */
            if ((cfg->iSocket = socket(PF_INET6, SOCK_STREAM, cfg->iProto)) == -1)
                return L2_ERR_SYS;

            /* if we have a socket, then bind ourselves to any port number    */
            IP6Localsock.sin6_family = AF_INET6;
            IP6Localsock.sin6_addr   = in6addr_any;
            IP6Localsock.sin6_port   = htons(0);

            if (bind(cfg->iSocket, (struct sockaddr *)&IP6Localsock,\
                sizeof(IP6Localsock))) {
                return L2_ERR_SYS;
            }

            if (connect(cfg->iSocket, (struct sockaddr *)&IP6Sockaddr,\
                sizeof(IP6Sockaddr))) {
                close(cfg->iSocket);
                return L2_ERR_SYS;
            }
        }
        else if (cfg->iProto == IPPROTO_UDP) {  /* with UDP we do not connect */
            if ((cfg->iSocket = socket(PF_INET, SOCK_DGRAM, cfg->iProto)) == -1)
                return L2_ERR_SYS;

            /* if we have a socket, then bind ourselves to any port number    */
            IP6Localsock.sin6_family = AF_INET6;
            IP6Localsock.sin6_addr   = in6addr_any;
            IP6Localsock.sin6_port   = htons(0);

            if (bind(cfg->iSocket, (struct sockaddr *)&IP6Localsock,\
                sizeof(IP6Localsock))) {
                return L2_ERR_SYS;
            }
        }

        return L2_OK;
    }

    return L2_ERR_USE;
}

/* write to channel */
static l2_result_t hook_write(l2_context_t *ctx, l2_channel_t *ch,
                              l2_level_t level, const char *buf, size_t buf_size)
{
    struct sockaddr_in IP4Sockaddr, IP6Sockaddr;
    l2_ch_socket_t    *cfg = (l2_ch_socket_t *)ctx->vp;
    size_t             sizeWrite;
    size_t             sizeRemain;

    /* parameter checks */
    if (cfg->iSocket == -1)
        return L2_ERR_ARG;

    if (cfg->iProto == IPPROTO_TCP) {
        /* write message to channel socket, but check to make   */
        /* sure that the whole message was successfully written */
        sizeWrite  = 0;
        sizeRemain = buf_size;
        while(sizeRemain) {
            sizeWrite  = send(cfg->iSocket, buf + sizeWrite, sizeRemain, 0);
            sizeRemain = sizeRemain - sizeWrite; /* how much is left? */

            if (sizeWrite == -1)
                return L2_ERR_SYS;
        }
    }
    else if (cfg->iProto == IPPROTO_UDP) {
        /* write message to the host target, but check to make  */
        /* sure that the whole message was successfully written */
        sizeWrite  = 0;
        sizeRemain = buf_size;
        while(sizeRemain) {
            if (cfg->iFamily == AF_INET) { /* IPv4 */
/* TODO !!! */  sizeWrite  = sendto(cfg->iSocket, buf + sizeWrite, sizeRemain, 0,\
/* Fill in  */      (struct sockaddr *)&IP4Sockaddr, sizeof(IP4Sockaddr));
/* the host */
/* address  */  sizeRemain = sizeRemain - sizeWrite; /* how much is left? */
/* structs  */
                if (sizeWrite == -1)
                    return L2_ERR_SYS;
            }
            else if (cfg->iFamily == AF_INET6) { /* IPv6 */
 /* TODO !!! */     sizeWrite  = sendto(cfg->iSocket, buf + sizeWrite, sizeRemain, 0,\
 /* Fill in  */         (struct sockaddr *)&IP6Sockaddr, sizeof(IP6Sockaddr));
 /* the host */
 /* address  */     sizeRemain = sizeRemain - sizeWrite; /* how much is left? */
 /* structs  */
                if (sizeWrite == -1)
                    return L2_ERR_USE;
            }
            else /* Neither IPv4 nor IPv6 */
                return L2_ERR_USE;
        }
    }

    return L2_OK;
}

/* close channel */
static l2_result_t hook_close(l2_context_t *ctx, l2_channel_t *ch)
{
    l2_ch_socket_t *cfg = (l2_ch_socket_t *)ctx->vp;

    /* parameter checks */
    if (cfg->iSocket == -1)
        return L2_ERR_USE;

    /* close channel socket */
    if ((shutdown(cfg->iSocket, SHUT_RDWR)) || (close(cfg->iSocket)))
        return L2_ERR_SYS;

    return L2_OK;
}

/* destroy channel */
static l2_result_t hook_destroy(l2_context_t *ctx, l2_channel_t *ch)
{
    l2_ch_socket_t *cfg = (l2_ch_socket_t *)ctx->vp;

    /* destroy channel configuration */
    free(cfg);

    return L2_OK;
}

/* exported channel handler structure */
l2_handler_t l2_handler_socket = {
    L2_CHANNEL_OUTPUT,
    hook_create,
    hook_configure,
    hook_open,
    hook_write,
    NULL,
    hook_close,
    hook_destroy
};