/*	udp_usrreq.c	6.6	84/08/21	*/

#include "../h/param.h"
#include "../h/dir.h"
#include "../h/user.h"
#include "../h/mbuf.h"
#include "../h/protosw.h"
#include "../h/socket.h"
#include "../h/socketvar.h"
#include "../h/errno.h"
#include "../h/stat.h"

#include "../net/if.h"
#include "../net/route.h"

#include "../netinet/in.h"
#include "../netinet/in_pcb.h"
#include "../netinet/in_systm.h"
#include "../netinet/ip.h"
#include "../netinet/ip_var.h"
#include "../netinet/ip_icmp.h"
#include "../netinet/udp.h"
#include "../netinet/udp_var.h"

/*
 * UDP protocol implementation.
 * Per RFC 768, August, 1980.
 */
udp_init()
{

	udb.inp_next = udb.inp_prev = &udb;
}

int	udpcksum = 0;
struct	sockaddr_in udp_in = { AF_INET };

udp_input(m0)
	struct mbuf *m0;
{
	register struct udpiphdr *ui;
	register struct inpcb *inp;
	register struct mbuf *m;
	int len;

	/*
	 * Get IP and UDP header together in first mbuf.
	 */
	m = m0;
	if ((m->m_off > MMAXOFF || m->m_len < sizeof (struct udpiphdr)) &&
	    (m = m_pullup(m, sizeof (struct udpiphdr))) == 0) {
		udpstat.udps_hdrops++;
		return;
	}
	ui = mtod(m, struct udpiphdr *);
	if (((struct ip *)ui)->ip_hl > (sizeof (struct ip) >> 2))
		ip_stripoptions((struct ip *)ui, (struct mbuf *)0);

	/*
	 * Make mbuf data length reflect UDP length.
	 * If not enough data to reflect UDP length, drop.
	 */
	len = ntohs((u_short)ui->ui_ulen);
	if (((struct ip *)ui)->ip_len != len) {
		if (len > ((struct ip *)ui)->ip_len) {
			udpstat.udps_badlen++;
			goto bad;
		}
		m_adj(m, len - ((struct ip *)ui)->ip_len);
		/* (struct ip *)ui->ip_len = len; */
	}

	/*
	 * Checksum extended UDP header and data.
	 */
	if (udpcksum && ui->ui_sum) {
		ui->ui_next = ui->ui_prev = 0;
		ui->ui_x1 = 0;
		ui->ui_len = htons((u_short)len);
		if (ui->ui_sum = in_cksum(m, len + sizeof (struct ip))) {
			udpstat.udps_badsum++;
			m_freem(m);
			return;
		}
	}

	/*
	 * Locate pcb for datagram.
	 */
	inp = in_pcblookup(&udb,
	    ui->ui_src, ui->ui_sport, ui->ui_dst, ui->ui_dport,
		INPLOOKUP_WILDCARD);
	if (inp == 0) {
		/* don't send ICMP response for broadcast packet */
		if (in_lnaof(ui->ui_dst) == INADDR_ANY)
			goto bad;
		icmp_error((struct ip *)ui, ICMP_UNREACH, ICMP_UNREACH_PORT);
		return;
	}

	/*
	 * Construct sockaddr format source address.
	 * Stuff source address and datagram in user buffer.
	 */
	udp_in.sin_port = ui->ui_sport;
	udp_in.sin_addr = ui->ui_src;
	m->m_len -= sizeof (struct udpiphdr);
	m->m_off += sizeof (struct udpiphdr);
	if (sbappendaddr(&inp->inp_socket->so_rcv, (struct sockaddr *)&udp_in,
	    m, (struct mbuf *)0) == 0)
		goto bad;
	sorwakeup(inp->inp_socket);
	return;
bad:
	m_freem(m);
}

udp_abort(inp)
	struct inpcb *inp;
{
	struct socket *so = inp->inp_socket;

	in_pcbdisconnect(inp);
	soisdisconnected(so);
}

udp_ctlinput(cmd, arg)
	int cmd;
	caddr_t arg;
{
	struct in_addr *sin;
	extern u_char inetctlerrmap[];

	if (cmd < 0 || cmd > PRC_NCMDS)
		return;
	switch (cmd) {

	case PRC_ROUTEDEAD:
		break;

	case PRC_QUENCH:
		break;

	/* these are handled by ip */
	case PRC_IFDOWN:
	case PRC_HOSTDEAD:
	case PRC_HOSTUNREACH:
		break;

	default:
		sin = &((struct icmp *)arg)->icmp_ip.ip_dst;
		in_pcbnotify(&udb, sin, (int)inetctlerrmap[cmd], udp_abort);
	}
}

udp_output(inp, m0)
	struct inpcb *inp;
	struct mbuf *m0;
{
	register struct mbuf *m;
	register struct udpiphdr *ui;
	register struct socket *so;
	register int len = 0;
	register struct route *ro;

	/*
	 * Calculate data length and get a mbuf
	 * for UDP and IP headers.
	 */
	for (m = m0; m; m = m->m_next)
		len += m->m_len;
	m = m_get(M_DONTWAIT, MT_HEADER);
	if (m == 0) {
		m_freem(m0);
		return (ENOBUFS);
	}

	/*
	 * Fill in mbuf with extended UDP header
	 * and addresses and length put into network format.
	 */
	m->m_off = MMAXOFF - sizeof (struct udpiphdr);
	m->m_len = sizeof (struct udpiphdr);
	m->m_next = m0;
	ui = mtod(m, struct udpiphdr *);
	ui->ui_next = ui->ui_prev = 0;
	ui->ui_x1 = 0;
	ui->ui_pr = IPPROTO_UDP;
	ui->ui_len = htons((u_short)len + sizeof (struct udphdr));
	ui->ui_src = inp->inp_laddr;
	ui->ui_dst = inp->inp_faddr;
	ui->ui_sport = inp->inp_lport;
	ui->ui_dport = inp->inp_fport;
	ui->ui_ulen = ui->ui_len;

	/*
	 * Stuff checksum and output datagram.
	 */
	ui->ui_sum = 0;
	if ((ui->ui_sum = in_cksum(m, sizeof (struct udpiphdr) + len)) == 0)
		ui->ui_sum = -1;
	((struct ip *)ui)->ip_len = sizeof (struct udpiphdr) + len;
	((struct ip *)ui)->ip_ttl = MAXTTL;
	so = inp->inp_socket;
	if (so->so_options & SO_DONTROUTE)
		return (ip_output(m, (struct mbuf *)0, (struct route *)0,
		    (so->so_state & SS_PRIV) | IP_ROUTETOIF));
	/*
	 * Use cached route for previous datagram if
	 * this is also to the same destination. 
	 *
	 * NB: We don't handle broadcasts because that
	 *     would require 3 subroutine calls.
	 */
	ro = &inp->inp_route;
#define	satosin(sa)	((struct sockaddr_in *)(sa))
	if (ro->ro_rt &&
	    satosin(&ro->ro_dst)->sin_addr.s_addr != ui->ui_dst.s_addr) {
		RTFREE(ro->ro_rt);
		ro->ro_rt = (struct rtentry *)0;
	}
	return (ip_output(m, (struct mbuf *)0, ro, so->so_state & SS_PRIV));
}

/*ARGSUSED*/
udp_usrreq(so, req, m, nam, rights)
	struct socket *so;
	int req;
	struct mbuf *m, *nam, *rights;
{
	struct inpcb *inp = sotoinpcb(so);
	int error = 0;

	if (rights && rights->m_len) {
		error = EINVAL;
		goto release;
	}
	if (inp == NULL && req != PRU_ATTACH) {
		error = EINVAL;
		goto release;
	}
	switch (req) {

	case PRU_ATTACH:
		if (inp != NULL) {
			error = EINVAL;
			break;
		}
		error = in_pcballoc(so, &udb);
		if (error)
			break;
		error = soreserve(so, 2048, 2048);
		if (error)
			break;
		break;

	case PRU_DETACH:
		if (inp == NULL) {
			error = ENOTCONN;
			break;
		}
		in_pcbdetach(inp);
		break;

	case PRU_BIND:
		error = in_pcbbind(inp, nam);
		break;

	case PRU_LISTEN:
		error = EOPNOTSUPP;
		break;

	case PRU_CONNECT:
		if (inp->inp_faddr.s_addr != INADDR_ANY) {
			error = EISCONN;
			break;
		}
		error = in_pcbconnect(inp, nam);
		if (error == 0)
			soisconnected(so);
		break;

	case PRU_CONNECT2:
		error = EOPNOTSUPP;
		break;

	case PRU_ACCEPT:
		error = EOPNOTSUPP;
		break;

	case PRU_DISCONNECT:
		if (inp->inp_faddr.s_addr == INADDR_ANY) {
			error = ENOTCONN;
			break;
		}
		in_pcbdisconnect(inp);
		soisdisconnected(so);
		break;

	case PRU_SHUTDOWN:
		socantsendmore(so);
		break;

	case PRU_SEND: {
		struct in_addr laddr;
		int s;

		if (nam) {
			laddr = inp->inp_laddr;
			if (inp->inp_faddr.s_addr != INADDR_ANY) {
				error = EISCONN;
				break;
			}
			/*
			 * Must block input while temporarily connected.
			 */
			s = splnet();
			error = in_pcbconnect(inp, nam);
			if (error) {
				splx(s);
				break;
			}
		} else {
			if (inp->inp_faddr.s_addr == INADDR_ANY) {
				error = ENOTCONN;
				break;
			}
		}
		error = udp_output(inp, m);
		m = NULL;
		if (nam) {
			in_pcbdisconnect(inp);
			splx(s);
			inp->inp_laddr = laddr;
		}
		}
		break;

	case PRU_ABORT:
		in_pcbdetach(inp);
		sofree(so);
		soisdisconnected(so);
		break;

	case PRU_SOCKADDR:
		in_setsockaddr(inp, nam);
		break;

	case PRU_PEERADDR:
		in_setpeeraddr(inp, nam);
		break;

	case PRU_SENSE:
		/*
		 * stat: don't bother with a blocksize.
		 */
		return (0);

	case PRU_SENDOOB:
	case PRU_FASTTIMO:
	case PRU_SLOWTIMO:
	case PRU_PROTORCV:
	case PRU_PROTOSEND:
		error =  EOPNOTSUPP;
		break;

	case PRU_CONTROL:
	case PRU_RCVD:
	case PRU_RCVOOB:
		return (EOPNOTSUPP);	/* do not free mbuf's */

	default:
		panic("udp_usrreq");
	}
release:
	if (m != NULL)
		m_freem(m);
	return (error);
}