/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) NGINX, Inc.
 */

#include <nxt_main.h>


static const char *nxt_socket_sockopt_name(nxt_uint_t level,
    nxt_uint_t sockopt);


nxt_socket_t
nxt_socket_create(nxt_task_t *task, nxt_uint_t domain, nxt_uint_t type,
    nxt_uint_t protocol, nxt_uint_t flags)
{
    nxt_socket_t  s;

#if (NXT_HAVE_SOCK_NONBLOCK)

    if (flags & NXT_NONBLOCK) {
        type |= SOCK_NONBLOCK;
    }

#endif

    s = socket(domain, type, protocol);

    if (nxt_slow_path(s == -1)) {
        nxt_alert(task, "socket(%ui, 0x%uXi, %ui) failed %E",
                  domain, type, protocol, nxt_socket_errno);
        return s;
    }

    nxt_debug(task, "socket(): %d", s);

#if !(NXT_HAVE_SOCK_NONBLOCK)

    if (flags & NXT_NONBLOCK) {
        if (nxt_slow_path(nxt_socket_nonblocking(task, s) != NXT_OK)) {
            nxt_socket_close(task, s);
            return -1;
        }
    }

#endif

    return s;
}


void
nxt_socket_close(nxt_task_t *task, nxt_socket_t s)
{
    if (nxt_fast_path(close(s) == 0)) {
        nxt_debug(task, "socket close(%d)", s);

    } else {
        nxt_alert(task, "socket close(%d) failed %E", s, nxt_socket_errno);
    }
}


void
nxt_socket_defer_accept(nxt_task_t *task, nxt_socket_t s, nxt_sockaddr_t *sa)
{
#if (NXT_HAVE_UNIX_DOMAIN)

    if (sa->u.sockaddr.sa_family == AF_UNIX) {
        /* Deferred accept() is not supported on AF_UNIX sockets. */
        return;
    }

#endif

#ifdef TCP_DEFER_ACCEPT

    /* Defer Linux accept() up to for 1 second. */
    (void) nxt_socket_setsockopt(task, s, IPPROTO_TCP, TCP_DEFER_ACCEPT, 1);

#endif
}


nxt_int_t
nxt_socket_getsockopt(nxt_task_t *task, nxt_socket_t s, nxt_uint_t level,
    nxt_uint_t sockopt)
{
    int        val;
    socklen_t  len;

    len = sizeof(val);

    if (nxt_fast_path(getsockopt(s, level, sockopt, &val, &len) == 0)) {
        nxt_debug(task, "getsockopt(%d, %ui, %s): %d",
                  s, level, nxt_socket_sockopt_name(level, sockopt), val);
        return val;
    }

    nxt_alert(task, "getsockopt(%d, %ui, %s) failed %E",
              s, level, nxt_socket_sockopt_name(level, sockopt),
              nxt_socket_errno);

    return -1;
}


nxt_int_t
nxt_socket_setsockopt(nxt_task_t *task, nxt_socket_t s, nxt_uint_t level,
    nxt_uint_t sockopt, int val)
{
    socklen_t  len;

    len = sizeof(val);

    if (nxt_fast_path(setsockopt(s, level, sockopt, &val, len) == 0)) {
        nxt_debug(task, "setsockopt(%d, %ui, %s): %d",
                  s, level, nxt_socket_sockopt_name(level, sockopt), val);
        return NXT_OK;
    }

    nxt_alert(task, "setsockopt(%d, %ui, %s, %d) failed %E",
              s, level, nxt_socket_sockopt_name(level, sockopt), val,
              nxt_socket_errno);

    return NXT_ERROR;
}


static const char *
nxt_socket_sockopt_name(nxt_uint_t level, nxt_uint_t sockopt)
{
    switch (level) {

    case SOL_SOCKET:
        switch (sockopt) {

        case SO_SNDBUF:
            return "SO_SNDBUF";

        case SO_RCVBUF:
            return "SO_RCVBUF";

        case SO_REUSEADDR:
            return "SO_REUSEADDR";

        case SO_TYPE:
            return "SO_TYPE";
        }

        break;

    case IPPROTO_TCP:
        switch (sockopt) {

        case TCP_NODELAY:
            return "TCP_NODELAY";

#ifdef TCP_DEFER_ACCEPT
        case TCP_DEFER_ACCEPT:
            return "TCP_DEFER_ACCEPT";
#endif
        }

        break;

#if (NXT_INET6)
    case IPPROTO_IPV6:

        switch (sockopt) {

        case IPV6_V6ONLY:
            return "IPV6_V6ONLY";
        }

        break;
#endif

    }

    return "";
}


nxt_int_t
nxt_socket_bind(nxt_task_t *task, nxt_socket_t s, nxt_sockaddr_t *sa,
    nxt_bool_t test)
{
    nxt_err_t  err;

    nxt_debug(task, "bind(%d, %*s)", s, (size_t) sa->length,
              nxt_sockaddr_start(sa));

    if (nxt_fast_path(bind(s, &sa->u.sockaddr, sa->socklen) == 0)) {
        return NXT_OK;
    }

    err = nxt_socket_errno;

    if (err == NXT_EADDRINUSE && test) {
        return NXT_DECLINED;
    }

    nxt_alert(task, "bind(%d, %*s) failed %E",
              s, (size_t) sa->length, nxt_sockaddr_start(sa), err);

    return NXT_ERROR;
}


nxt_int_t
nxt_socket_connect(nxt_task_t *task, nxt_socket_t s, nxt_sockaddr_t *sa)
{
    nxt_err_t   err;
    nxt_int_t   ret;
    nxt_uint_t  level;

    nxt_debug(task, "connect(%d, %*s)",
              s, (size_t) sa->length, nxt_sockaddr_start(sa));

    if (connect(s, &sa->u.sockaddr, sa->socklen) == 0) {
        return NXT_OK;
    }

    err = nxt_socket_errno;

    switch (err) {

    case NXT_EINPROGRESS:
        nxt_debug(task, "connect(%d, %*s) in progress",
                  s, (size_t) sa->length, nxt_sockaddr_start(sa));
        return NXT_AGAIN;

    case NXT_ECONNREFUSED:
#if (NXT_LINUX)
    case NXT_EAGAIN:
        /*
         * Linux returns EAGAIN instead of ECONNREFUSED
         * for UNIX sockets if a listen queue is full.
         */
#endif
        level = NXT_LOG_ERR;
        ret = NXT_DECLINED;
        break;

    case NXT_ECONNRESET:
    case NXT_ENETDOWN:
    case NXT_ENETUNREACH:
    case NXT_EHOSTDOWN:
    case NXT_EHOSTUNREACH:
        level = NXT_LOG_ERR;
        ret = NXT_ERROR;
        break;

    default:
        level = NXT_LOG_ALERT;
        ret = NXT_ERROR;
    }

    nxt_log(task, level, "connect(%d, %*s) failed %E",
            s, (size_t) sa->length, nxt_sockaddr_start(sa), err);

    return ret;
}


void
nxt_socket_shutdown(nxt_task_t *task, nxt_socket_t s, nxt_uint_t how)
{
    nxt_err_t   err;
    nxt_uint_t  level;

    if (nxt_fast_path(shutdown(s, how) == 0)) {
        nxt_debug(task, "shutdown(%d, %ui)", s, how);
        return;
    }

    err = nxt_socket_errno;

    switch (err) {

    case NXT_ENOTCONN:
        level = NXT_LOG_DEBUG;
        break;

    case NXT_ECONNRESET:
    case NXT_ENETDOWN:
    case NXT_ENETUNREACH:
    case NXT_EHOSTDOWN:
    case NXT_EHOSTUNREACH:
        level = NXT_LOG_ERR;
        break;

    default:
        level = NXT_LOG_ALERT;
    }

    nxt_log(task, level, "shutdown(%d, %ui) failed %E", s, how, err);
}


nxt_err_t
nxt_socket_error(nxt_socket_t s)
{
    int        ret, err;
    socklen_t  len;

    err = 0;
    len = sizeof(int);
    /*  
     * Linux and BSDs return 0 and store a pending error in the err argument; 
     * Solaris returns -1 and sets the errno.
     */  
    ret = getsockopt(s, SOL_SOCKET, SO_ERROR, (void *) &err, &len);

    if (nxt_slow_path(ret == -1)) {
        err = nxt_errno;
    }   

    return err;
}


nxt_uint_t
nxt_socket_error_level(nxt_err_t err)
{
    switch (err) {

    case NXT_EPIPE:
    case NXT_ECONNRESET:
    case NXT_ENOTCONN:
    case NXT_ETIMEDOUT:
    case NXT_ENETDOWN:
    case NXT_ENETUNREACH:
    case NXT_EHOSTDOWN:
    case NXT_EHOSTUNREACH:
        return NXT_LOG_INFO;

    default:
        return NXT_LOG_ALERT;
    }
}