datagram.c

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/*
 *  common UDP/RAW code
 *  Linux INET implementation
 *
 * Authors:
 *  Hideaki YOSHIFUJI <[email protected]>
 *
 *  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.
 */

#include <linux/types.h>
#include <linux/module.h>
#include <linux/ip.h>
#include <linux/in.h>
#include <net/ip.h>
#include <net/sock.h>
#include <net/route.h>
#include <net/tcp_states.h>

int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
    struct inet_sock *inet = inet_sk(sk);
    struct sockaddr_in *usin = (struct sockaddr_in *) uaddr;
    struct flowi4 *fl4;
    struct rtable *rt;
    __be32 saddr;
    int oif;
    int err;


    if (addr_len < sizeof(*usin))
        return -EINVAL;

    if (usin->sin_family != AF_INET)
        return -EAFNOSUPPORT;

    sk_dst_reset(sk);

    lock_sock(sk);

    oif = sk->sk_bound_dev_if;
    saddr = inet->inet_saddr;
    if (ipv4_is_multicast(usin->sin_addr.s_addr)) {
        if (!oif)
            oif = inet->mc_index;
        if (!saddr)
            saddr = inet->mc_addr;
    }
    fl4 = &inet->cork.fl.u.ip4;
    rt = ip_route_connect(fl4, usin->sin_addr.s_addr, saddr,
                  RT_CONN_FLAGS(sk), oif,
                  sk->sk_protocol,
                  inet->inet_sport, usin->sin_port, sk, true);
    if (IS_ERR(rt)) {
        err = PTR_ERR(rt);
        if (err == -ENETUNREACH)
            IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
        goto out;
    }

    if ((rt->rt_flags & RTCF_BROADCAST) && !sock_flag(sk, SOCK_BROADCAST)) {
        ip_rt_put(rt);
        err = -EACCES;
        goto out;
    }
    if (!inet->inet_saddr)
        inet->inet_saddr = fl4->saddr;  /* Update source address */
    if (!inet->inet_rcv_saddr) {
        inet->inet_rcv_saddr = fl4->saddr;
        if (sk->sk_prot->rehash)
            sk->sk_prot->rehash(sk);
    }
    inet->inet_daddr = fl4->daddr;
    inet->inet_dport = usin->sin_port;
    sk->sk_state = TCP_ESTABLISHED;
    inet->inet_id = jiffies;

    sk_dst_set(sk, &rt->dst);
    err = 0;
out:
    release_sock(sk);
    return err;
}
EXPORT_SYMBOL(ip4_datagram_connect);