pfsense · f-bor · Sep 17, 2020
diff --git a/net/isc-dhcp44-relay/Makefile b/net/isc-dhcp44-relay/Makefile
@@ -6,4 +6,8 @@ COMMENT=	The ISC Dynamic Host Configuration Protocol relay
 SUBSYS=		relay
 MASTERDIR=	${.CURDIR}/../isc-dhcp44-server
 
+EXTRA_PATCHES=  ${.CURDIR}/files/patch-common__bpf.c \
+                ${.CURDIR}/files/patch-common__packet.c \
+                ${.CURDIR}/files/patch-includes__dhcp.h
+
 .include "${MASTERDIR}/Makefile"
diff --git a/net/isc-dhcp44-relay/files/patch-common__bpf.c b/net/isc-dhcp44-relay/files/patch-common__bpf.c
@@ -0,0 +1,167 @@
+--- common/bpf.c.orig	2020-09-17 06:51:06.537106000 +0200
++++ common/bpf.c	2020-09-17 06:52:05.627807000 +0200
+@@ -197,6 +197,7 @@
+ 	/* Otherwise, drop it. */
+ 	BPF_STMT (BPF_RET + BPF_K, 0),
+ };
++struct bpf_insn * dhcp_virtual_filter = NULL;
+
+ #if defined(RELAY_PORT)
+ /*
+@@ -235,6 +236,8 @@
+
+ int dhcp_bpf_relay_filter_len =
+ 	sizeof dhcp_bpf_relay_filter / sizeof (struct bpf_insn);
++
++struct bpf_insn * dhcp_virtual_relay_filter = NULL;
+ #endif
+
+ #if defined (DEC_FDDI)
+@@ -242,6 +245,7 @@
+ #endif
+
+ int dhcp_bpf_filter_len = sizeof dhcp_bpf_filter / sizeof (struct bpf_insn);
++
+ #if defined (HAVE_TR_SUPPORT)
+ struct bpf_insn dhcp_bpf_tr_filter [] = {
+         /* accept all token ring packets due to variable length header */
+@@ -259,7 +263,88 @@
+ #endif /* HAVE_TR_SUPPORT */
+ #endif /* USE_LPF_RECEIVE || USE_BPF_RECEIVE */
+
++void patch_virtual_filter(filter)
++	struct bpf_insn * filter;
++{
++	/* The address family is 4 bytes long */
++	filter[0].k = 0;
++	filter[0].code = BPF_LD + BPF_W + BPF_ABS;
++
++        /* From Kea:
++		The address family is AF_INET. It can't be hardcoded in the BPF program
++		because we need to make the host to network order conversion using htonl
++		and conversion can't be done within the BPF program structure as it
++		doesn't work on some systems. */
++	filter[1].k = htonl(AF_INET);
++
++	/* Patch the BPF program to account for the difference
++		in length between ethernet headers (14), and virtual
++		link headers (4, -10).
++		XXX changes to filter program may require changes to
++		XXX the insn number(s) used below! */
++	filter[2].k -= 10;
++	filter[4].k -= 10;
++	filter[6].k -= 10;
++	filter[7].k -= 10;
++}
++
++struct bpf_insn * get_virtual_filter()
++{
++	if ( dhcp_virtual_filter == NULL ) {
++		dhcp_virtual_filter = dmalloc (sizeof dhcp_bpf_filter, MDL);
++		if (!dhcp_virtual_filter)
++			log_fatal ("No memory for virtual filter.");
++		memcpy (dhcp_virtual_filter, dhcp_bpf_filter, sizeof dhcp_bpf_filter);
++		patch_virtual_filter(dhcp_virtual_filter);
++	}
++	return dhcp_virtual_filter;
++}
++
++#if defined(RELAY_PORT)
++struct bpf_insn * get_virtual_relay_filter()
++{
++	if ( dhcp_virtual_relay_filter == NULL ) {
++		dhcp_virtual_relay_filter = dmalloc (sizeof dhcp_bpf_relay_filter, MDL);
++		if (!dhcp_virtual_relay_filter)
++			log_fatal ("No memory for virtual relay filter.");
++		memcpy (dhcp_virtual_relay_filter, dhcp_bpf_relay_filter, sizeof dhcp_bpf_relay_filter);
++		patch_virtual_filter(dhcp_virtual_relay_filter);
++	}
++	return dhcp_virtual_relay_filter;
++}
++#endif
++
+ #if defined (USE_BPF_RECEIVE)
++
++static int is_virtual(name)
++	const char * name;
++{
++	int ret = 0;
++	struct ifaddrs *ifa;
++	struct ifaddrs *p;
++	struct sockaddr_dl *sa;
++
++	if (getifaddrs(&ifa) != 0) {
++		log_fatal("Error getting interface information; %m");
++	}
++
++	/*
++	* Loop through our interfaces finding a match.
++	*/
++	sa = NULL;
++	for (p=ifa; (p != NULL) && (sa == NULL); p = p->ifa_next) {
++		if ((p->ifa_addr->sa_family == AF_LINK) && !strcmp(p->ifa_name, name)) {
++			sa = (struct sockaddr_dl *)p->ifa_addr;
++		}
++	}
++
++	if (sa != NULL && sa->sdl_type == IFT_TUNNEL )
++		ret = 1;
++
++	freeifaddrs(ifa);
++	return ret;
++}
++
+ void if_register_receive (info)
+ 	struct interface_info *info;
+ {
+@@ -272,6 +357,9 @@
+ #ifdef DEC_FDDI
+ 	int link_layer;
+ #endif /* DEC_FDDI */
++	int virtual = 0;
++
++	virtual = is_virtual(info->name);
+
+ 	/* Open a BPF device and hang it on this interface... */
+ 	info -> rfdesc = if_register_bpf (info);
+@@ -343,7 +431,10 @@
+ 		p.bf_insns = bpf_fddi_filter;
+ 	} else
+ #endif /* DEC_FDDI */
+-	p.bf_insns = dhcp_bpf_filter;
++	if ( virtual )
++		p.bf_insns = get_virtual_filter();
++	else
++		p.bf_insns = dhcp_bpf_filter;
+
+         /* Patch the server port into the BPF  program...
+ 	   XXX changes to filter program may require changes
+@@ -355,9 +446,12 @@
+ 		 * also on the user UDP port.
+ 		 */
+ 		p.bf_len = dhcp_bpf_relay_filter_len;
+-		p.bf_insns = dhcp_bpf_relay_filter;
++		if ( virtual )
++			p.bf_insns = get_virtual_relay_filter();
++		else
++			p.bf_insns = dhcp_bpf_relay_filter;
+
+-		dhcp_bpf_relay_filter [10].k = ntohs (relay_port);
++		p.bf_insns [10].k = ntohs (relay_port);
+ 	}
+ #endif
+ 	p.bf_insns [8].k = ntohs (local_port);
+@@ -627,7 +721,11 @@
+ 	 * Pull out the appropriate information.
+ 	 */
+         switch (sa->sdl_type) {
+-                case IFT_ETHER:
++		case IFT_TUNNEL:
++                        hw->hlen = 1;
++                        hw->hbuf[0] = HTYPE_VIRTUAL;
++                        break;
++		case IFT_ETHER:
+ #if defined (IFT_L2VLAN)
+ 		case IFT_L2VLAN:
+ #endif
+
diff --git a/net/isc-dhcp44-relay/files/patch-common__packet.c b/net/isc-dhcp44-relay/files/patch-common__packet.c
@@ -0,0 +1,27 @@
+--- common/packet.c.orig	2020-09-17 06:51:06.550928000 +0200
++++ common/packet.c	2020-09-17 06:52:05.628196000 +0200
+@@ -201,6 +201,14 @@
+  * Doesn't support infiniband yet as the supported oses shouldn't get here
+  */
+
++#define VIRTUAL_HEADER_SIZE	4
++ssize_t decode_virtual_header (from)
++     struct hardware *from;
++{
++	from -> hlen = 0;
++	return VIRTUAL_HEADER_SIZE;
++}
++
+ ssize_t decode_hw_header (interface, buf, bufix, from)
+      struct interface_info *interface;
+      unsigned char *buf;
+@@ -219,6 +227,8 @@
+ 	case HTYPE_INFINIBAND:
+ 		log_error("Attempt to decode hw header for infiniband");
+ 		return (0);
++	case HTYPE_VIRTUAL:
++		return (decode_virtual_header(from));
+ 	case HTYPE_ETHER:
+ 	default:
+ 		return (decode_ethernet_header(interface, buf, bufix, from));
+
diff --git a/net/isc-dhcp44-relay/files/patch-includes__dhcp.h b/net/isc-dhcp44-relay/files/patch-includes__dhcp.h
@@ -0,0 +1,11 @@
+--- includes/dhcp.h.orig        2020-09-17 06:51:06.557515000 +0200
++++ includes/dhcp.h     2020-09-17 06:52:05.628324000 +0200
+@@ -73,6 +73,7 @@
+
+ /* Possible values for hardware type (htype) field... */
+ #define HTYPE_ETHER    1               /* Ethernet 10Mbps              */
++#define HTYPE_VIRTUAL  2               /* Loopback / tunnel            */
+ #define HTYPE_IEEE802  6               /* IEEE 802.2 Token Ring...     */
+ #define HTYPE_FDDI     8               /* FDDI...                      */
+ #define HTYPE_INFINIBAND  32           /* IP over Infiniband           */
+