Adding changes to ipfw and the kernel to support ip packet diversion..

This stuff should not be too destructive if the IPDIVERT is not compiled in..
 be aware that this changes the size of the ip_fw struct
so ipfw needs to be recompiled to use it.. more changes coming to clean this up.

1 files changed, 365 insertions, 0 deletions

diff --git a/sys/netinet/ip_divert.c b/sys/netinet/ip_divert.c
new file mode 100644
index 000000000000..7720f8484268
--- /dev/null
+++ b/sys/netinet/ip_divert.c
@@ -0,0 +1,365 @@
+/*
+ * Copyright (c) 1982, 1986, 1988, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	$Id: ip_divert.c,v 1.2 1996/06/14 00:28:38 archie Exp $
+ */
+
+#include <sys/param.h>
+#include <sys/queue.h>
+#include <sys/malloc.h>
+#include <sys/mbuf.h>
+#include <sys/socket.h>
+#include <sys/protosw.h>
+#include <sys/socketvar.h>
+#include <sys/errno.h>
+#include <sys/systm.h>
+
+#include <net/if.h>
+#include <net/route.h>
+
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+#include <netinet/in_pcb.h>
+#include <netinet/in_var.h>
+#include <netinet/ip_var.h>
+
+/*
+ * Divert sockets
+ */
+
+/*
+ * Allocate enough space to hold a full IP packet
+ */
+#define	DIVSNDQ		(65536 + 100)
+#define	DIVRCVQ		(65536 + 100)
+
+/* Global variables */
+
+/*
+ * ip_input() and ip_output() set this secret value before calling us to
+ * let us know which divert port to divert a packet to; this is done so
+ * we can use the existing prototype for struct protosw's pr_input().
+ * This is stored in host order.
+ */
+u_short ip_divert_port;
+
+/*
+ * We set this value to a non-zero port number when we want the call to
+ * ip_fw_chk() in ip_input() or ip_output() to ignore ``divert <port>''
+ * chain entries. This is stored in host order.
+ */
+u_short ip_divert_ignore;
+
+/* Internal variables */
+
+static struct inpcbhead divcb;
+static struct inpcbinfo divcbinfo;
+
+static u_long	div_sendspace = DIVSNDQ;	/* XXX sysctl ? */
+static u_long	div_recvspace = DIVRCVQ;	/* XXX sysctl ? */
+
+/* Optimization: have this preinitialized */
+static struct sockaddr_in divsrc = { sizeof(divsrc), AF_INET };
+
+/* Internal functions */
+
+static int div_output(struct socket *so,
+		struct mbuf *m, struct mbuf *addr, struct mbuf *control);
+
+/*
+ * Initialize divert connection block queue.
+ */
+void
+div_init(void)
+{
+	LIST_INIT(&divcb);
+	divcbinfo.listhead = &divcb;
+	/*
+	 * XXX We don't use the hash list for divert IP, but it's easier
+	 * to allocate a one entry hash list than it is to check all
+	 * over the place for hashbase == NULL.
+	 */
+	divcbinfo.hashbase = phashinit(1, M_PCB, &divcbinfo.hashsize);
+}
+
+/*
+ * Setup generic address and protocol structures
+ * for div_input routine, then pass them along with
+ * mbuf chain. ip->ip_len is assumed to have had
+ * the header length (hlen) subtracted out already.
+ * We tell whether the packet was incoming or outgoing
+ * by seeing if hlen == 0, which is a hack.
+ */
+void
+div_input(struct mbuf *m, int hlen)
+{
+	register struct ip *ip = mtod(m, struct ip *);
+	register struct inpcb *inp;
+	register struct socket *sa;
+
+	/* Sanity check */
+	if (ip_divert_port == 0)
+		panic("div_input");
+
+	/* Record divert port */
+	divsrc.sin_port = htons(ip_divert_port);
+
+	/* Restore packet header fields */
+	ip->ip_len += hlen;
+	HTONS(ip->ip_len);
+	HTONS(ip->ip_off);
+
+	/* Record receive interface address, if any */
+	divsrc.sin_addr.s_addr = 0;
+	if (hlen) {
+		struct ifaddr *ifa;
+
+		/* More fields affected by ip_input() */
+		HTONS(ip->ip_id);
+
+		/* Find IP address for recieve interface */
+		for (ifa = m->m_pkthdr.rcvif->if_addrlist;
+		    ifa != NULL; ifa = ifa->ifa_next) {
+			if (ifa->ifa_addr == NULL)
+				continue;
+			if (ifa->ifa_addr->sa_family != AF_INET)
+				continue;
+			divsrc.sin_addr =
+			    ((struct sockaddr_in *) ifa->ifa_addr)->sin_addr;
+			break;
+		}
+	}
+
+	/* Put packet on socket queue, if any */
+	sa = NULL;
+	for (inp = divcb.lh_first; inp != NULL; inp = inp->inp_list.le_next) {
+		if (inp->inp_lport == htons(ip_divert_port))
+			sa = inp->inp_socket;
+	}
+	if (sa) {
+		if (sbappendaddr(&sa->so_rcv, (struct sockaddr *)&divsrc,
+				m, (struct mbuf *)0) == 0)
+			m_freem(m);
+		else
+			sorwakeup(sa);
+	} else {
+		m_freem(m);
+		ipstat.ips_noproto++;
+		ipstat.ips_delivered--;
+        }
+}
+
+/*
+ * Deliver packet back into the IP processing machinery.
+ *
+ * If no address specified, or address is 0.0.0.0, send to ip_output();
+ * otherwise, send to ip_input() and mark as having been received on
+ * the interface with that address.
+ *
+ * If no address specified, or dest port is 0, allow packet to divert
+ * back to this socket; otherwise, don't.
+ */
+static int
+div_output(so, m, addr, control)
+	struct socket *so;
+	register struct mbuf *m;
+	struct mbuf *addr, *control;
+{
+	register struct inpcb *const inp = sotoinpcb(so);
+	register struct ip *const ip = mtod(m, struct ip *);
+	struct sockaddr_in *sin = NULL;
+	int error = 0;
+
+	if (control)
+		m_freem(control);		/* XXX */
+	if (addr)
+		sin = mtod(addr, struct sockaddr_in *);
+
+	/* Loopback avoidance option */
+	if (sin && sin->sin_port)
+		ip_divert_ignore = ntohs(inp->inp_lport);
+
+	/* Reinject packet into the system as incoming or outgoing */
+	if (!sin || sin->sin_addr.s_addr == 0) {
+		/* Don't allow both user specified and setsockopt options,
+		   and don't allow packet length sizes that will crash */
+		if (((ip->ip_hl != (sizeof (*ip) >> 2)) && inp->inp_options) ||
+		     ((u_short)ntohs(ip->ip_len) > m->m_pkthdr.len)) {
+			error = EINVAL;
+			goto cantsend;
+		}
+
+		/* Convert fields to host order for ip_output() */
+		NTOHS(ip->ip_len);
+		NTOHS(ip->ip_off);
+
+		/* Send packet to output processing */
+		ipstat.ips_rawout++;			/* XXX */
+		error = ip_output(m, inp->inp_options, &inp->inp_route,
+			(so->so_options & SO_DONTROUTE) |
+			IP_ALLOWBROADCAST | IP_RAWOUTPUT, inp->inp_moptions);
+	} else {
+		struct ifaddr *ifa;
+
+		/* Find receive interface with the given IP address */
+		sin->sin_port = 0;
+		if ((ifa = ifa_ifwithaddr((struct sockaddr *) sin)) == 0) {
+			error = EADDRNOTAVAIL;
+			goto cantsend;
+		}
+		m->m_pkthdr.rcvif = ifa->ifa_ifp;
+
+		/* Send packet to input processing */
+		ip_input(m);
+	}
+
+	/* Reset for next time (and other packets) */
+	ip_divert_ignore = 0;
+	return error;
+
+cantsend:
+	ip_divert_ignore = 0;
+	m_freem(m);
+	return error;
+}
+
+/*ARGSUSED*/
+int
+div_usrreq(so, req, m, nam, control)
+	register struct socket *so;
+	int req;
+	struct mbuf *m, *nam, *control;
+{
+	register int error = 0;
+	register struct inpcb *inp = sotoinpcb(so);
+	int s = 0;
+
+	if (inp == NULL && req != PRU_ATTACH) {
+		error = EINVAL;
+		goto release;
+	}
+	switch (req) {
+
+	case PRU_ATTACH:
+		if (inp)
+			panic("div_attach");
+		if ((so->so_state & SS_PRIV) == 0) {
+			error = EACCES;
+			break;
+		}
+		if ((error = soreserve(so, div_sendspace, div_recvspace)) ||
+		    (error = in_pcballoc(so, &divcbinfo)))
+			break;
+		inp = (struct inpcb *)so->so_pcb;
+		inp->inp_ip.ip_p = (int)nam;	/* XXX */
+		inp->inp_flags |= INP_HDRINCL;
+		/* The socket is always "connected" because
+		   we always know "where" to send the packet */
+		so->so_state |= SS_ISCONNECTED;
+		break;
+
+	case PRU_DISCONNECT:
+		if ((so->so_state & SS_ISCONNECTED) == 0) {
+			error = ENOTCONN;
+			break;
+		}
+		/* FALLTHROUGH */
+	case PRU_ABORT:
+		soisdisconnected(so);
+		/* FALLTHROUGH */
+	case PRU_DETACH:
+		if (inp == 0)
+			panic("div_detach");
+		in_pcbdetach(inp);
+		break;
+
+	case PRU_BIND:
+		s = splnet();
+		error = in_pcbbind(inp, nam);
+		splx(s);
+		break;
+
+	/*
+	 * Mark the connection as being incapable of further input.
+	 */
+	case PRU_SHUTDOWN:
+		socantsendmore(so);
+		break;
+
+	case PRU_SEND:
+		/* Packet must have a header (but that's about it) */
+		if (m->m_len < sizeof (struct ip) ||
+		    (m = m_pullup(m, sizeof (struct ip))) == 0) {
+			ipstat.ips_toosmall++;
+			error = EINVAL;
+			break;
+		}
+
+		/* Send packet */
+		error = div_output(so, m, nam, control); 
+		m = NULL;
+		break;
+
+	case PRU_SOCKADDR:
+		in_setsockaddr(inp, nam);
+		break;
+
+	case PRU_SENSE:
+		/*
+		 * stat: don't bother with a blocksize.
+		 */
+		return (0);
+
+	/*
+	 * Not supported.
+	 */
+	case PRU_CONNECT:
+	case PRU_CONNECT2:
+	case PRU_CONTROL:
+	case PRU_RCVOOB:
+	case PRU_RCVD:
+	case PRU_LISTEN:
+	case PRU_ACCEPT:
+	case PRU_SENDOOB:
+	case PRU_PEERADDR:
+		error = EOPNOTSUPP;
+		break;
+
+	default:
+		panic("div_usrreq");
+	}
+release:
+	if (m)
+		m_freem(m);
+	return (error);
+}