C++ RT_CONN_FLAGS函数代码示例

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 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);

	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;
	}
	err = ip_route_connect(&rt, usin->sin_addr.s_addr, saddr,
			       RT_CONN_FLAGS(sk), oif,
			       sk->sk_protocol,
			       inet->inet_sport, usin->sin_port, sk, 1);
	if (err) {
		if (err == -ENETUNREACH)
			IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
		return err;
	}

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

	sk_dst_set(sk, &rt->dst);
	return(0);
}

static struct dst_entry* dccp_v4_route_skb(struct net *net, struct sock *sk,
					   struct sk_buff *skb)
{
	struct rtable *rt;
	const struct iphdr *iph = ip_hdr(skb);
	struct flowi4 fl4 = {
		.flowi4_oif = inet_iif(skb),
		.daddr = iph->saddr,
		.saddr = iph->daddr,
		.flowi4_tos = RT_CONN_FLAGS(sk),
		.flowi4_proto = sk->sk_protocol,
		.fl4_sport = dccp_hdr(skb)->dccph_dport,
		.fl4_dport = dccp_hdr(skb)->dccph_sport,
	};

	security_skb_classify_flow(skb, flowi4_to_flowi(&fl4));
	rt = ip_route_output_flow(net, &fl4, sk);
	if (IS_ERR(rt)) {
		IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
		return NULL;
	}

	return &rt->dst;
}

static int dccp_v4_send_response(const struct sock *sk, struct request_sock *req)
{
	int err = -1;
	struct sk_buff *skb;
	struct dst_entry *dst;
	struct flowi4 fl4;

	dst = inet_csk_route_req(sk, &fl4, req);
	if (dst == NULL)
		goto out;

	skb = dccp_make_response(sk, dst, req);
	if (skb != NULL) {
		const struct inet_request_sock *ireq = inet_rsk(req);
		struct dccp_hdr *dh = dccp_hdr(skb);

		dh->dccph_checksum = dccp_v4_csum_finish(skb, ireq->ir_loc_addr,
							      ireq->ir_rmt_addr);
		rcu_read_lock();
		err = ip_build_and_send_pkt(skb, sk, ireq->ir_loc_addr,
					    ireq->ir_rmt_addr,
					    rcu_dereference(ireq->ireq_opt));
		rcu_read_unlock();
		err = net_xmit_eval(err);
	}

out:
	dst_release(dst);
	return err;
}

/*
  This will route a SYN-ACK, i.e., the response to a request to open a
  new connection.
 */
struct dst_entry *serval_ipv4_req_route(struct sock *sk,
                                        struct request_sock *rsk,
                                        int protocol,
                                        u32 saddr,
                                        u32 daddr)
{
	struct rtable *rt;
	struct ip_options *opt = NULL; /* inet_rsk(req)->opt; */
        struct flowi fl;

        serval_flow_init_output(&fl, sk->sk_bound_dev_if, sk->sk_mark,
                                RT_CONN_FLAGS(sk), 0, protocol,
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,28))
                                inet_sk_flowi_flags(sk),
#else
                                0,
#endif
                                daddr, saddr, 0, 0);
        
	serval_security_req_classify_flow(rsk, &fl);

	rt = serval_ip_route_output_flow(sock_net(sk), &fl, sk, 0);
        
        if (!rt)
		goto no_route;
        
	if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway)
		goto route_err;

	return route_dst(rt);

route_err:
	ip_rt_put(rt);
no_route:
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,25))
	IP_INC_STATS_BH(sock_net(sk), IPSTATS_MIB_OUTNOROUTES);
#else
	IP_INC_STATS(IPSTATS_MIB_OUTNOROUTES);
#endif
	return NULL;
}

int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
	const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
	struct inet_sock *inet = inet_sk(sk);
	struct dccp_sock *dp = dccp_sk(sk);
	__be16 orig_sport, orig_dport;
	__be32 daddr, nexthop;
	struct flowi4 *fl4;
	struct rtable *rt;
	int err;
	struct ip_options_rcu *inet_opt;

	dp->dccps_role = DCCP_ROLE_CLIENT;

	if (addr_len < sizeof(struct sockaddr_in))
		return -EINVAL;

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

	nexthop = daddr = usin->sin_addr.s_addr;

	inet_opt = rcu_dereference_protected(inet->inet_opt,
					     sock_owned_by_user(sk));
	if (inet_opt != NULL && inet_opt->opt.srr) {
		if (daddr == 0)
			return -EINVAL;
		nexthop = inet_opt->opt.faddr;
	}

	orig_sport = inet->inet_sport;
	orig_dport = usin->sin_port;
	fl4 = &inet->cork.fl.u.ip4;
	rt = ip_route_connect(fl4, nexthop, inet->inet_saddr,
			      RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
			      IPPROTO_DCCP,
			      orig_sport, orig_dport, sk);
	if (IS_ERR(rt))
		return PTR_ERR(rt);

	if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
		ip_rt_put(rt);
		return -ENETUNREACH;
	}

	if (inet_opt == NULL || !inet_opt->opt.srr)
		daddr = fl4->daddr;

	if (inet->inet_saddr == 0)
		inet->inet_saddr = fl4->saddr;
	sk_rcv_saddr_set(sk, inet->inet_saddr);
	inet->inet_dport = usin->sin_port;
	sk_daddr_set(sk, daddr);

	inet_csk(sk)->icsk_ext_hdr_len = 0;
	if (inet_opt)
		inet_csk(sk)->icsk_ext_hdr_len = inet_opt->opt.optlen;
	/*
	 * Socket identity is still unknown (sport may be zero).
	 * However we set state to DCCP_REQUESTING and not releasing socket
	 * lock select source port, enter ourselves into the hash tables and
	 * complete initialization after this.
	 */
	dccp_set_state(sk, DCCP_REQUESTING);
	err = inet_hash_connect(&dccp_death_row, sk);
	if (err != 0)
		goto failure;

	rt = ip_route_newports(fl4, rt, orig_sport, orig_dport,
			       inet->inet_sport, inet->inet_dport, sk);
	if (IS_ERR(rt)) {
		err = PTR_ERR(rt);
		rt = NULL;
		goto failure;
	}
	/* OK, now commit destination to socket.  */
	sk_setup_caps(sk, &rt->dst);

	dp->dccps_iss = secure_dccp_sequence_number(inet->inet_saddr,
						    inet->inet_daddr,
						    inet->inet_sport,
						    inet->inet_dport);
	inet->inet_id = dp->dccps_iss ^ jiffies;

	err = dccp_connect(sk);
	rt = NULL;
	if (err != 0)
		goto failure;
out:
	return err;
failure:
	/*
	 * This unhashes the socket and releases the local port, if necessary.
	 */
	dccp_set_state(sk, DCCP_CLOSED);
	ip_rt_put(rt);
	sk->sk_route_caps = 0;
	inet->inet_dport = 0;
	goto out;
}

int dccp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct dccp_sock *dp = dccp_sk(sk);
	const struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
	struct rtable *rt;
	__be32 daddr, nexthop;
	int tmp;
	int err;

	dp->dccps_role = DCCP_ROLE_CLIENT;

	if (addr_len < sizeof(struct sockaddr_in))
		return -EINVAL;

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

	nexthop = daddr = usin->sin_addr.s_addr;
	if (inet->opt != NULL && inet->opt->srr) {
		if (daddr == 0)
			return -EINVAL;
		nexthop = inet->opt->faddr;
	}

	tmp = ip_route_connect(&rt, nexthop, inet->inet_saddr,
			       RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
			       IPPROTO_DCCP,
			       inet->inet_sport, usin->sin_port, sk, 1);
	if (tmp < 0)
		return tmp;

	if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
		ip_rt_put(rt);
		return -ENETUNREACH;
	}

	if (inet->opt == NULL || !inet->opt->srr)
		daddr = rt->rt_dst;

	if (inet->inet_saddr == 0)
		inet->inet_saddr = rt->rt_src;
	inet->inet_rcv_saddr = inet->inet_saddr;

	inet->inet_dport = usin->sin_port;
	inet->inet_daddr = daddr;

	inet_csk(sk)->icsk_ext_hdr_len = 0;
	if (inet->opt != NULL)
		inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;
	/*
	 * Socket identity is still unknown (sport may be zero).
	 * However we set state to DCCP_REQUESTING and not releasing socket
	 * lock select source port, enter ourselves into the hash tables and
	 * complete initialization after this.
	 */
	dccp_set_state(sk, DCCP_REQUESTING);
	err = inet_hash_connect(&dccp_death_row, sk);
	if (err != 0)
		goto failure;

	err = ip_route_newports(&rt, IPPROTO_DCCP, inet->inet_sport,
				inet->inet_dport, sk);
	if (err != 0)
		goto failure;

	/* OK, now commit destination to socket.  */
	sk_setup_caps(sk, &rt->u.dst);

	dp->dccps_iss = secure_dccp_sequence_number(inet->inet_saddr,
						    inet->inet_daddr,
						    inet->inet_sport,
						    inet->inet_dport);
	inet->inet_id = dp->dccps_iss ^ jiffies;

	err = dccp_connect(sk);
	rt = NULL;
	if (err != 0)
		goto failure;
out:
	return err;
failure:
	/*
	 * This unhashes the socket and releases the local port, if necessary.
	 */
	dccp_set_state(sk, DCCP_CLOSED);
	ip_rt_put(rt);
	sk->sk_route_caps = 0;
	inet->inet_dport = 0;
	goto out;
}

static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		       size_t len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct ipcm_cookie ipc;
	struct rtable *rt = NULL;
	struct flowi4 fl4;
	int free = 0;
	__be32 daddr;
	__be32 saddr;
	u8  tos;
	int err;
	struct ip_options_data opt_copy;

	err = -EMSGSIZE;
	if (len > 0xFFFF)
		goto out;

	/*
	 *	Check the flags.
	 */

	err = -EOPNOTSUPP;
	if (msg->msg_flags & MSG_OOB)	/* Mirror BSD error message */
		goto out;               /* compatibility */

	/*
	 *	Get and verify the address.
	 */

	if (msg->msg_namelen) {
		struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
		err = -EINVAL;
		if (msg->msg_namelen < sizeof(*usin))
			goto out;
		if (usin->sin_family != AF_INET) {
			pr_info_once("%s: %s forgot to set AF_INET. Fix it!\n",
				     __func__, current->comm);
			err = -EAFNOSUPPORT;
			if (usin->sin_family)
				goto out;
		}
		daddr = usin->sin_addr.s_addr;
		/* ANK: I did not forget to get protocol from port field.
		 * I just do not know, who uses this weirdness.
		 * IP_HDRINCL is much more convenient.
		 */
	} else {
		err = -EDESTADDRREQ;
		if (sk->sk_state != TCP_ESTABLISHED)
			goto out;
		daddr = inet->inet_daddr;
	}

	ipc.addr = inet->inet_saddr;
	ipc.opt = NULL;
	ipc.tx_flags = 0;
	ipc.oif = sk->sk_bound_dev_if;

	if (msg->msg_controllen) {
		err = ip_cmsg_send(sock_net(sk), msg, &ipc);
		if (err)
			goto out;
		if (ipc.opt)
			free = 1;
	}

	saddr = ipc.addr;
	ipc.addr = daddr;

	if (!ipc.opt) {
		struct ip_options_rcu *inet_opt;

		rcu_read_lock();
		inet_opt = rcu_dereference(inet->inet_opt);
		if (inet_opt) {
			memcpy(&opt_copy, inet_opt,
			       sizeof(*inet_opt) + inet_opt->opt.optlen);
			ipc.opt = &opt_copy.opt;
		}
		rcu_read_unlock();
	}

	if (ipc.opt) {
		err = -EINVAL;
		/* Linux does not mangle headers on raw sockets,
		 * so that IP options + IP_HDRINCL is non-sense.
		 */
		if (inet->hdrincl)
			goto done;
		if (ipc.opt->opt.srr) {
			if (!daddr)
				goto done;
			daddr = ipc.opt->opt.faddr;
		}
	}
	tos = RT_CONN_FLAGS(sk);
	if (msg->msg_flags & MSG_DONTROUTE)
		tos |= RTO_ONLINK;

//.........这里部分代码省略.........

static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		       size_t len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct ipcm_cookie ipc;
	struct rtable *rt = NULL;
	int free = 0;
	__be32 daddr;
	__be32 saddr;
	u8  tos;
	int err;

	err = -EMSGSIZE;
	if (len > 0xFFFF)
		goto out;

	/*
	 *	Check the flags.
	 */

	err = -EOPNOTSUPP;
	if (msg->msg_flags & MSG_OOB)	/* Mirror BSD error message */
		goto out;               /* compatibility */

	/*
	 *	Get and verify the address.
	 */

	if (msg->msg_namelen) {
		struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
		err = -EINVAL;
		if (msg->msg_namelen < sizeof(*usin))
			goto out;
		if (usin->sin_family != AF_INET) {
			static int complained;
			if (!complained++)
				printk(KERN_INFO "%s forgot to set AF_INET in "
						 "raw sendmsg. Fix it!\n",
						 current->comm);
			err = -EAFNOSUPPORT;
			if (usin->sin_family)
				goto out;
		}
		daddr = usin->sin_addr.s_addr;
		/* ANK: I did not forget to get protocol from port field.
		 * I just do not know, who uses this weirdness.
		 * IP_HDRINCL is much more convenient.
		 */
	} else {
		err = -EDESTADDRREQ;
		if (sk->sk_state != TCP_ESTABLISHED)
			goto out;
		daddr = inet->inet_daddr;
	}

	ipc.addr = inet->inet_saddr;
	ipc.opt = NULL;
	ipc.tx_flags = 0;
	ipc.oif = sk->sk_bound_dev_if;

	if (msg->msg_controllen) {
		err = ip_cmsg_send(sock_net(sk), msg, &ipc);
		if (err)
			goto out;
		if (ipc.opt)
			free = 1;
	}

	saddr = ipc.addr;
	ipc.addr = daddr;

	if (!ipc.opt)
		ipc.opt = inet->opt;

	if (ipc.opt) {
		err = -EINVAL;
		/* Linux does not mangle headers on raw sockets,
		 * so that IP options + IP_HDRINCL is non-sense.
		 */
		if (inet->hdrincl)
			goto done;
		if (ipc.opt->srr) {
			if (!daddr)
				goto done;
			daddr = ipc.opt->faddr;
		}
	}
	tos = RT_CONN_FLAGS(sk);
	if (msg->msg_flags & MSG_DONTROUTE)
		tos |= RTO_ONLINK;

	if (ipv4_is_multicast(daddr)) {
		if (!ipc.oif)
			ipc.oif = inet->mc_index;
		if (!saddr)
			saddr = inet->mc_addr;
	}

	{
		struct flowi4 fl4 = {
//.........这里部分代码省略.........

static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		       size_t len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct ipcm_cookie ipc;
	struct rtable *rt = NULL;
	int free = 0;
	u32 daddr;
	u32 saddr;
	u8  tos;
	int err;

	err = -EMSGSIZE;
	if (len < 0 || len > 0xFFFF)
		goto out;

	/*
	 *	Check the flags.
	 */

	err = -EOPNOTSUPP;
	if (msg->msg_flags & MSG_OOB)	/* Mirror BSD error message */
		goto out;               /* compatibility */
			 
	/*
	 *	Get and verify the address. 
	 */

	if (msg->msg_namelen) {
		struct sockaddr_in *usin = (struct sockaddr_in*)msg->msg_name;
		err = -EINVAL;
		if (msg->msg_namelen < sizeof(*usin))
			goto out;
		if (usin->sin_family != AF_INET) {
			static int complained;
			if (!complained++)
				printk(KERN_INFO "%s forgot to set AF_INET in "
						 "raw sendmsg. Fix it!\n",
						 current->comm);
			err = -EAFNOSUPPORT;
			if (usin->sin_family)
				goto out;
		}
		daddr = usin->sin_addr.s_addr;
		/* ANK: I did not forget to get protocol from port field.
		 * I just do not know, who uses this weirdness.
		 * IP_HDRINCL is much more convenient.
		 */
	} else {
		err = -EDESTADDRREQ;
		if (sk->sk_state != TCP_ESTABLISHED) 
			goto out;
		daddr = inet->daddr;
	}

	ipc.addr = inet->saddr;
	ipc.opt = NULL;
	ipc.oif = sk->sk_bound_dev_if;

	if (msg->msg_controllen) {
		err = ip_cmsg_send(msg, &ipc);
		if (err)
			goto out;
		if (ipc.opt)
			free = 1;
	}

	saddr = ipc.addr;
	ipc.addr = daddr;

	if (!ipc.opt)
		ipc.opt = inet->opt;

	if (ipc.opt) {
		err = -EINVAL;
		/* Linux does not mangle headers on raw sockets,
		 * so that IP options + IP_HDRINCL is non-sense.
		 */
		if (inet->hdrincl)
			goto done;
		if (ipc.opt->srr) {
			if (!daddr)
				goto done;
			daddr = ipc.opt->faddr;
		}
	}
	tos = RT_CONN_FLAGS(sk);
	if (msg->msg_flags & MSG_DONTROUTE)
		tos |= RTO_ONLINK;

	if (MULTICAST(daddr)) {
		if (!ipc.oif)
			ipc.oif = inet->mc_index;
		if (!saddr)
			saddr = inet->mc_addr;
	}

	{
		struct flowi fl = { .oif = ipc.oif,
				    .nl_u = { .ip4_u =
//.........这里部分代码省略.........

/* This will initiate an outgoing connection. */
int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct tcp_sock *tp = tcp_sk(sk);
	struct sockaddr_in *usin = (struct sockaddr_in *)uaddr;
	struct rtable *rt;
	u32 daddr, nexthop;
	int tmp;
	int err;

	if (addr_len < sizeof(struct sockaddr_in))
		return -EINVAL;

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

	nexthop = daddr = usin->sin_addr.s_addr;
	if (inet->opt && inet->opt->srr) {
		if (!daddr)
			return -EINVAL;
		nexthop = inet->opt->faddr;
	}

	tmp = ip_route_connect(&rt, nexthop, inet->saddr,
			       RT_CONN_FLAGS(sk), sk->sk_bound_dev_if,
			       IPPROTO_TCP,
			       inet->sport, usin->sin_port, sk);
	if (tmp < 0)
		return tmp;

	if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
		ip_rt_put(rt);
		return -ENETUNREACH;
	}

	if (!inet->opt || !inet->opt->srr)
		daddr = rt->rt_dst;

	if (!inet->saddr)
		inet->saddr = rt->rt_src;
	inet->rcv_saddr = inet->saddr;

	if (tp->rx_opt.ts_recent_stamp && inet->daddr != daddr) {
		/* Reset inherited state */
		tp->rx_opt.ts_recent	   = 0;
		tp->rx_opt.ts_recent_stamp = 0;
		tp->write_seq		   = 0;
	}

	if (tcp_death_row.sysctl_tw_recycle &&
	    !tp->rx_opt.ts_recent_stamp && rt->rt_dst == daddr) {
		struct inet_peer *peer = rt_get_peer(rt);

		/* VJ's idea. We save last timestamp seen from
		 * the destination in peer table, when entering state TIME-WAIT
		 * and initialize rx_opt.ts_recent from it, when trying new connection.
		 */

		if (peer && peer->tcp_ts_stamp + TCP_PAWS_MSL >= xtime.tv_sec) {
			tp->rx_opt.ts_recent_stamp = peer->tcp_ts_stamp;
			tp->rx_opt.ts_recent = peer->tcp_ts;
		}
	}

	inet->dport = usin->sin_port;
	inet->daddr = daddr;

	inet_csk(sk)->icsk_ext_hdr_len = 0;
	if (inet->opt)
		inet_csk(sk)->icsk_ext_hdr_len = inet->opt->optlen;

	tp->rx_opt.mss_clamp = 536;

	/* Socket identity is still unknown (sport may be zero).
	 * However we set state to SYN-SENT and not releasing socket
	 * lock select source port, enter ourselves into the hash tables and
	 * complete initialization after this.
	 */
	tcp_set_state(sk, TCP_SYN_SENT);
	err = inet_hash_connect(&tcp_death_row, sk);
	if (err)
		goto failure;

	err = ip_route_newports(&rt, IPPROTO_TCP, inet->sport, inet->dport, sk);
	if (err)
		goto failure;

	/* OK, now commit destination to socket.  */
	sk->sk_gso_type = SKB_GSO_TCPV4;
	sk_setup_caps(sk, &rt->u.dst);

	if (!tp->write_seq)
		tp->write_seq = secure_tcp_sequence_number(inet->saddr,
							   inet->daddr,
							   inet->sport,
							   usin->sin_port);

	inet->id = tp->write_seq ^ jiffies;

//.........这里部分代码省略.........

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;	
	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;
}

int serval_ipv4_xmit(struct sk_buff *skb)
{
        struct sock *sk = skb->sk;
        int err = 0;
#if defined(OS_LINUX_KERNEL)

	/*
          This is pretty much a copy paste from ip_queue_xmit
          (ip_output.c), but which modifications that take into
          account Serval specific stuff.
          
          It will route the packet according to the IP stack's routing
          table and output for standard IP output processing.
         */
        struct iphdr *iph;
        struct rtable *rt;
        struct inet_sock *inet = inet_sk(sk);
	struct ip_options *opt = NULL; /*inet->inet_opt; */
        int ifindex;

	/*
	   The SAL has dirtied the control block that IP expects to be
	zeroed out. 
	We need to make sure it is initialized again. Otherwise, there
	might be stack corruptions when IP functions try to read the
	IPCB. (This happens in, e.g., icmp_send when reading ip options.)  
	*/
        memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
        
	/* 
         * Skip all of this if the packet is already routed,
         */
        rcu_read_lock();

        rt = skb_rtable(skb);

        if (rt != NULL) {
                LOG_PKT("Packet already routed\n");
                goto packet_routed;
        }
        /* Make sure we can route this packet. */
        rt = (struct rtable *)__sk_dst_check(sk, 0);

        if (skb->dev) {
                ifindex = skb->dev->ifindex;
        } else {
                ifindex = sk->sk_bound_dev_if;
        }

        if (rt == NULL) {
                struct flowi fl;

                serval_flow_init_output(&fl, ifindex, 
                                        sk->sk_mark, 
                                        RT_CONN_FLAGS(sk), 0,
                                        skb->protocol,
#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,28))
                                        inet_sk_flowi_flags(sk),
#else
                                        0,
#endif
                                        inet->inet_daddr,
                                        inet->inet_saddr,
                                        0, 0);
                
                serval_security_sk_classify_flow(sk, &fl);
                
                rt = serval_ip_route_output_flow(sock_net(sk), &fl, sk, 0);

                if (!rt) {
                        LOG_DBG("No route!\n");
                        err = -EHOSTUNREACH;
                        rcu_read_unlock();
                        goto drop;
                }

                /* Setup the socket to use this route in the future */
                sk_setup_caps(sk, route_dst(rt));

        } else {
                LOG_PKT("Using route already associated with socket\n");
        }
        
#if defined(ENABLE_DEBUG)
        {
                char src[18], dst[18];
                LOG_PKT("Route found %s -> %s %s\n",
                        inet_ntop(AF_INET, &rt->rt_src, 
                                  src, sizeof(src)),
                        inet_ntop(AF_INET, &rt->rt_dst, 
                                  dst, sizeof(dst)),
                        route_dst(rt)->dev ? 
                        route_dst(rt)->dev->name : "(null)");
        }
#endif

#if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 35))
        skb_dst_set(skb, dst_clone(route_dst(rt)));
#else
        skb_dst_set_noref(skb, route_dst(rt));
//.........这里部分代码省略.........