/*
 * Copyright 2000, International Business Machines Corporation and others.
 * All Rights Reserved.
 * 
 * This software has been released under the terms of the IBM Public
 * License.  For details, see the LICENSE file in the top-level source
 * directory or online at http://www.openafs.org/dl/license10.html
 */

#include <afsconfig.h>
#include "afs/param.h"

RCSID
    ("$Header: /cvs/openafs/src/rx/DUX/rx_knet.c,v 1.11 2004/08/09 00:58:50 shadow Exp $");

#ifdef AFS_DUX40_ENV
#include "rx/rx_kcommon.h"


static struct protosw parent_proto;	/* udp proto switch */
static void rxk_input(struct mbuf *am, int iphlen);
static void rxk_fasttimo(void);

/* start intercepting basic calls */
void
rxk_init()
{
    register struct protosw *tpro, *last;
    if (rxk_initDone)
	return;

    last = inetdomain.dom_protoswNPROTOSW;
    for (tpro = inetdomain.dom_protosw; tpro < last; tpro++)
	if (tpro->pr_protocol == IPPROTO_UDP) {
	    /* force UDP checksumming on for AFS    */
	    extern int udpcksum;
	    udpcksum = 1;
	    memcpy(&parent_proto, tpro, sizeof(parent_proto));
	    tpro->pr_input = rxk_input;
	    tpro->pr_fasttimo = rxk_fasttimo;
	    /*
	     * don't bother with pr_drain and pr_ctlinput
	     * until we have something to do
	     */
	    rxk_initDone = 1;
	    return;
	}
    osi_Panic("inet:no udp");
}


static void
rxk_input(struct mbuf *am, int iphlen)
{
    void (*tproc) ();
    register unsigned short *tsp;
    int hdr;
    struct udphdr *tu;
    register struct ip *ti;
    struct udpiphdr *tvu;
    register int i;
    char *phandle;
    afs_int32 code;
    struct sockaddr_in taddr;
    int tlen;
    short port;
    int data_len, comp_sum;

    SPLVAR;
    NETPRI;

    /* make sure we have base ip and udp headers in first mbuf */
    if (iphlen > sizeof(struct ip)) {
	ip_stripoptions(am, NULL, NULL);
	iphlen = sizeof(struct ip);
    }

    if (am->m_len < sizeof(struct udpiphdr)) {
	am = m_pullup(am, sizeof(struct udpiphdr));
	if (!am) {
	    USERPRI;
	    return;
	}
    }

    ti = mtod(am, struct ip *);
    /* skip basic ip hdr */
    tu = (struct udphdr *)(((char *)ti) + sizeof(struct ip));

    /* now read the port out */
    port = tu->uh_dport;

    if (port) {
	for (tsp = rxk_ports, i = 0; i < MAXRXPORTS; i++) {
	    if (*tsp++ == port) {
		/* checksum the packet */
		/*
		 * Make mbuf data length reflect UDP length.
		 * If not enough data to reflect UDP length, drop.
		 */
		tvu = (struct udpiphdr *)ti;
		tlen = ntohs((u_short) tvu->ui_ulen);
		if ((int)ti->ip_len != tlen) {
		    if (tlen > (int)ti->ip_len) {
			m_free(am);
			USERPRI;
			return;
		    }
		    m_adj(am, tlen - (int)ti->ip_len);
		}
		/* deliver packet to rx */
		taddr.sin_family = AF_INET;	/* compute source address */
		taddr.sin_port = tu->uh_sport;
		taddr.sin_addr.s_addr = ti->ip_src.s_addr;
		taddr.sin_len = sizeof(taddr);
		tvu = (struct udpiphdr *)ti;	/* virtual udp structure, for cksum */
		/* handle the checksum.  Note that this code damages the actual ip
		 * header (replacing it with the virtual one, which is the same size),
		 * so we must ensure we get everything out we need, first */
		if (tu->uh_sum != 0) {
		    /* if the checksum is there, always check it. It's crazy not
		     * to, unless you can really be sure that your
		     * underlying network (and interfaces and drivers and
		     * DMA hardware, etc!) is error-free. First, fill
		     * in entire virtual ip header. */
		    tvu->ui_i.fill[0] = 0;
		    tvu->ui_i.fill[1] = 0;
		    tvu->ui_x1 = 0;
		    tvu->ui_len = tvu->ui_ulen;
		    tlen = ntohs((unsigned short)(tvu->ui_ulen));
		    if (in_cksum(am, sizeof(struct ip) + tlen)) {
			/* checksum, including cksum field, doesn't come out 0, so
			 * this packet is bad */
			m_freem(am);
			USERPRI;
			return;
		    }
		}

		/*
		 * 28 is IP (20) + UDP (8) header.  ulen includes
		 * udp header, and we *don't* tell RX about udp
		 * header either.  So, we remove those 8 as well.
		 */
		data_len = ntohs(tu->uh_ulen);
		data_len -= 8;
		AFS_RXGLOCK();
		if (!(*rxk_GetPacketProc) (&phandle, data_len)) {
		    if (rx_mb_to_packet(am, m_freem, 28, data_len, phandle)) {
			/* XXX should just increment counter here.. */
			printf("rx: truncated UDP packet\n");
			rxi_FreePacket(phandle);
		    } else
			(*rxk_PacketArrivalProc) (phandle, &taddr,
						  rxk_portRocks[i], data_len);
		} else
		    m_freem(am);
		AFS_RXGUNLOCK();
		USERPRI;
		return;
	    }
	}
    }

    /* if we get here, try to deliver packet to udp */
    if (tproc = parent_proto.pr_input)
	(*tproc) (am, iphlen);
    USERPRI;
    return;
}


/* 
 * UDP fast timer to raise events for all but Solaris and NCR. 
 * Called about 5 times per second (at unknown priority?).  Must go to
 * splnet or obtain global lock before touching anything significant.
 */
static void
rxk_fasttimo(void)
{
    void (*tproc) ();
    struct clock temp;

    /* do rx fasttimo processing here */
    rxevent_RaiseEvents(&temp);
    if (tproc = parent_proto.pr_fasttimo)
	(*tproc) ();
}


/* rx_NetSend - send asize bytes at adata from asocket to host at addr.
 *
 * Now, why do we allocate a new buffer when we could theoretically use the one
 * pointed to by adata?  Because PRU_SEND returns after queueing the message,
 * not after sending it.  If the sender changes the data after queueing it,
 * we'd see the already-queued data change.  One attempt to fix this without
 * adding a copy would be to have this function wait until the datagram is
 * sent; however this doesn't work well.  In particular, if a host is down, and
 * an ARP fails to that host, this packet will be queued until the ARP request
 * comes back, which could be hours later.  We can't block in this routine that
 * long, since it prevents RPC timeouts from happening.
 */
/* XXX In the brave new world, steal the data bufs out of the rx_packet iovec,
 * and just queue those.  XXX
 */

/* set lock on sockbuf sb; can't call sblock since we're at interrupt level
 * sometimes */
static
trysblock(sb)
     register struct sockbuf *sb;
{
    AFS_STATCNT(trysblock);
    if (sb->sb_flags & SB_LOCK) {
	return -1;		/* can't lock socket */
    }
    sb->sb_flags |= SB_LOCK;
    return 0;
}

int
osi_NetSend(osi_socket asocket, struct sockaddr_in *addr, struct iovec *dvec,
	    int nvec, afs_int32 asize, int istack)
{
    register struct mbuf *tm, *um;
    register afs_int32 code;
    int s;
    struct mbuf *top = 0;
    register struct mbuf *m, **mp;
    int len;
    char *tdata;
    caddr_t tpa;
    int i, tl, rlen;
    int mlen;
    int haveGlock;

    AFS_STATCNT(osi_NetSend);

/* Actually, the Ultrix way is as good as any for us, so we don't bother with
 * special mbufs any more.  Used to think we could get away with not copying
 * the data to the interface, but there's no way to tell the caller not to
 * reuse the buffers after sending, so we lost out on that trick anyway */

    s = splnet();
    mp = &top;
    i = 0;
    tdata = dvec[i].iov_base;
    tl = dvec[i].iov_len;
    while (1) {
	mlen = MLEN;
	if (top == 0) {
	    MGETHDR(m, M_DONTWAIT, MT_DATA);
	    if (!m) {
		splx(s);
		return 1;
	    }
	    mlen = MHLEN;
	    m->m_pkthdr.len = 0;
	    m->m_pkthdr.rcvif = NULL;
	} else
	    MGET(m, M_DONTWAIT, MT_DATA);
	if (!m) {
	    /* can't get an mbuf, give up */
	    if (top)
		m_freem(top);	/* free mbuf list we're building */
	    splx(s);
	    return 1;
	}
	/*
	 * WARNING: the `4 * MLEN' is somewhat dubious.  It is better than
	 * `NBPG', which may have no relation to `CLBYTES'.  Also, `CLBYTES'
	 * may be so large that we never use clusters, resulting in far
	 * too many mbufs being used.  It is often better to briefly use
	 * a cluster, even if we are only using a portion of it.  Since
	 * we are on the xmit side, it shouldn't end up sitting on a queue
	 * for a potentially unbounded time (except perhaps if we are talking
	 * to ourself).
	 */
	if (asize >= 4 * MLEN) {	/* try to get cluster mbuf */
	    register struct mbuf *p;

	    /* different algorithms for getting cluster mbuf */
	    MCLGET(m, M_DONTWAIT);
	    if ((m->m_flags & M_EXT) == 0)
		goto nopages;
	    mlen = MCLBYTES;

	    /* now compute usable size */
	    len = MIN(mlen, asize);
/* Should I look at MAPPED_MBUFS??? */
	} else {
	  nopages:
	    len = MIN(mlen, asize);
	}
	m->m_len = 0;
	*mp = m;		/* XXXX */
	top->m_pkthdr.len += len;
	tpa = mtod(m, caddr_t);
	while (len) {
	    rlen = MIN(len, tl);
	    memcpy(tpa, tdata, rlen);
	    asize -= rlen;
	    len -= rlen;
	    tpa += rlen;
	    m->m_len += rlen;
	    tdata += rlen;
	    tl -= rlen;
	    if (tl <= 0) {
		i++;
		if (i > nvec) {
		    /* shouldn't come here! */
		    asize = 0;	/* so we make progress toward completion */
		    break;
		}
		tdata = dvec[i].iov_base;
		tl = dvec[i].iov_len;
	    }
	}
	*mp = m;
	mp = &m->m_next;
	if (asize <= 0)
	    break;
    }
    tm = top;

    tm->m_act = NULL;

    /* setup mbuf corresponding to destination address */
    um = m_get(M_DONTWAIT, MT_SONAME);
    if (!um) {
	if (top)
	    m_freem(top);	/* free mbuf chain */
	/* if this were vfs40, we'd do sbunlock(asocket, &asocket->so_snd), but
	 * we don't do the locking at all for vfs40 systems */
	splx(s);
	return 1;
    }
    memcpy(mtod(um, caddr_t), addr, sizeof(*addr));
    um->m_len = sizeof(*addr);
    /* note that udp_usrreq frees funny mbuf.  We hold onto data, but mbuf
     * around it is gone.  we free address ourselves.  */
    haveGlock = ISAFS_GLOCK();
    if (haveGlock) {
	AFS_GUNLOCK();
    }
    SOCKET_LOCK(asocket);
    code = (*asocket->so_proto->pr_usrreq) (asocket, PRU_SEND, tm, um, 0);
    SOCKET_UNLOCK(asocket);
    if (haveGlock) {
	AFS_GLOCK();
    }
    splx(s);
    m_free(um);

    return code;
}

#endif /* AFS_DUX40_ENV */
