Add an ARP packet processor

Makefile

@@ -52,6 +52,7 @@ LIB_C_FILES += rtemsbsd/local/pci_if.c
 LIB_C_FILES += rtemsbsd/local/usb_if.c
 LIB_C_FILES += rtemsbsd/rtems/ipsec_get_policylen.c
 LIB_C_FILES += rtemsbsd/rtems/rtems-bsd-assert.c
+LIB_C_FILES += rtemsbsd/rtems/rtems-bsd-arp-processor.c
 LIB_C_FILES += rtemsbsd/rtems/rtems-bsd-autoconf.c
 LIB_C_FILES += rtemsbsd/rtems/rtems-bsd-bus-dma.c
 LIB_C_FILES += rtemsbsd/rtems/rtems-bsd-bus-dma-mbuf.c

freebsd-to-rtems.py

@@ -639,6 +639,7 @@ rtems.addRTEMSSourceFiles(
 		'local/usb_if.c',
 		'rtems/ipsec_get_policylen.c',
 		'rtems/rtems-bsd-assert.c',
+		'rtems/rtems-bsd-arp-processor.c',
 		'rtems/rtems-bsd-autoconf.c',
 		'rtems/rtems-bsd-bus-dma.c',
 		'rtems/rtems-bsd-bus-dma-mbuf.c',

rtemsbsd/include/rtems/bsd/util.h

@@ -34,6 +34,8 @@
 
 #include <sys/types.h>
 
+#include <net/if.h>
+#include <net/if_arp.h>
 #include <net/ethernet.h>
 
 #include <stdint.h>
@@ -57,6 +59,24 @@ extern "C" {
 int
 rtems_bsd_get_ethernet_addr(const char *ifname, uint8_t eaddr[ETHER_ADDR_LEN]);
 
+typedef void (*rtems_bsd_arp_processor)(void *arg, int fd,
+    const uint8_t eaddr[ETHER_ADDR_LEN], const struct arphdr *ar,
+    uint32_t spa, uint32_t tpa, const uint8_t *sha, const uint8_t *tha);
+
+typedef struct rtems_bsd_arp_processor_context rtems_bsd_arp_processor_context;
+
+rtems_bsd_arp_processor_context *
+rtems_bsd_arp_processor_create(const char *ifname);
+
+int
+rtems_bsd_arp_processor_get_file_descriptor(
+    const rtems_bsd_arp_processor_context *ctx);
+
+int
+rtems_bsd_arp_processor_process(
+    rtems_bsd_arp_processor_context *ctx,
+    rtems_bsd_arp_processor processor, void *arg);
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */

rtemsbsd/rtems/rtems-bsd-arp-processor.c

@@ -0,0 +1,253 @@
+/*
+ * Copyright (c) 2014 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Dornierstr. 4
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * Copyright (c) 2006-2013 Roy Marples <roy@marples.name>
+ *
+ * Some parts are derived from the dhcpcd sources.
+ *
+ * http://roy.marples.name/projects/dhcpcd
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ */
+
+#include <rtems/bsd/util.h>
+
+#include <sys/cdefs.h>
+#include <sys/ioctl.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <net/bpf.h>
+#include <net/if_dl.h>
+#include <arpa/inet.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <ifaddrs.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct rtems_bsd_arp_processor_context {
+	int fd;
+	uint8_t eaddr[ETHER_ADDR_LEN];
+	size_t buf_size;
+	uint8_t buf[];
+};
+
+#ifndef BPF_ETHCOOK
+# define BPF_ETHCOOK 0
+#endif
+#ifndef BPF_WHOLEPACKET
+# define BPF_WHOLEPACKET ~0U
+#endif
+static const struct bpf_insn arp_bpf_filter[] = {
+	/* Make sure this is an ARP packet... */
+	BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 12),
+	BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_ARP, 0, 3),
+	/* Make sure this is an ARP REQUEST... */
+	BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20 + BPF_ETHCOOK),
+	BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REQUEST, 2, 0),
+	/* or ARP REPLY... */
+	BPF_STMT(BPF_LD + BPF_H + BPF_ABS, 20 + BPF_ETHCOOK),
+	BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 0, 1),
+	/* If we passed all the tests, ask for the whole packet. */
+	BPF_STMT(BPF_RET + BPF_K, BPF_WHOLEPACKET),
+	/* Otherwise, drop it. */
+	BPF_STMT(BPF_RET + BPF_K, 0)
+};
+
+static const size_t arp_bpf_filter_len =
+    sizeof(arp_bpf_filter) / sizeof(arp_bpf_filter[0]);
+
+static void
+process_arp_packet(const uint8_t *pkt, size_t pkt_size, int fd,
+    const uint8_t eaddr[ETHER_ADDR_LEN], rtems_bsd_arp_processor processor,
+    void *arg)
+{
+	struct arphdr ar;
+	uint32_t spa;
+	uint32_t tpa;
+	const uint8_t *sha;
+	const uint8_t *tha;
+
+	/* We must have a full ARP header */
+	if (pkt_size < sizeof(ar))
+		return;
+
+	memcpy(&ar, pkt, sizeof(ar));
+
+	/* Protocol must be IP. */
+	if (ar.ar_pro != htons(ETHERTYPE_IP))
+		return;
+
+	if (ar.ar_pln != sizeof(spa))
+		return;
+
+	/* Only these types are recognised */
+	if (ar.ar_op != htons(ARPOP_REPLY) &&
+	    ar.ar_op != htons(ARPOP_REQUEST))
+		return;
+
+	/* Get pointers to the hardware addresses */
+	sha = pkt + sizeof(ar);
+	tha = sha + ar.ar_hln + ar.ar_pln;
+
+	/* Ensure we got all the data */
+	if ((tha + ar.ar_hln + ar.ar_pln) - pkt > pkt_size)
+		return;
+
+	/* Ignore messages from ourself */
+	if (ar.ar_hln == ETHER_ADDR_LEN &&
+	    memcmp(sha, &eaddr[0], ETHER_ADDR_LEN) == 0)
+		return;
+
+	/* Copy out the IP addresses */
+	memcpy(&spa, sha + ar.ar_hln, ar.ar_pln);
+	memcpy(&tpa, tha + ar.ar_hln, ar.ar_pln);
+
+	(*processor)(arg, fd, eaddr, &ar, spa, tpa, sha, tha);
+}
+
+rtems_bsd_arp_processor_context *
+rtems_bsd_arp_processor_create(const char *ifname)
+{
+	rtems_bsd_arp_processor_context *ctx = NULL;
+	int fd = -1;
+	struct ifreq ifr;
+	int buf_len;
+	size_t buf_size;
+	struct bpf_version pv;
+	struct bpf_program pf;
+	int flags;
+	int rv;
+
+	fd = open("/dev/bpf", O_RDWR);
+	if (fd < 0) {
+		goto error;
+	}
+
+	rv = ioctl(fd, BIOCVERSION, &pv);
+	if (rv != 0 || pv.bv_major != BPF_MAJOR_VERSION ||
+	    pv.bv_minor < BPF_MINOR_VERSION) {
+		goto error;
+	}
+
+	memset(&ifr, 0, sizeof(ifr));
+	strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
+	rv = ioctl(fd, BIOCSETIF, &ifr);
+	if (rv != 0) {
+		goto error;
+	}
+
+	rv = ioctl(fd, BIOCGBLEN, &buf_len);
+	if (rv != 0 || buf_len <= 0) {
+		goto error;
+	}
+	buf_size = (size_t) buf_len;
+
+	flags = 1;
+	rv = ioctl(fd, BIOCIMMEDIATE, &flags);
+	if (rv != 0) {
+		goto error;
+	}
+
+	pf.bf_insns = __DECONST(struct bpf_insn *, arp_bpf_filter);
+	pf.bf_len = arp_bpf_filter_len;
+	rv = ioctl(fd, BIOCSETF, &pf);
+	if (rv != 0) {
+		goto error;
+	}
+
+	ctx = malloc(sizeof(*ctx) + buf_size);
+	if (ctx == NULL) {
+		goto error;
+	}
+
+	rv = rtems_bsd_get_ethernet_addr(ifname, &ctx->eaddr[0]);
+	if (rv != 0) {
+		goto error;
+	}
+
+	ctx->fd = fd;
+	ctx->buf_size = buf_size;
+
+	return ctx;
+
+error:
+	close(fd);
+	free(ctx);
+
+	return NULL;
+}
+
+int
+rtems_bsd_arp_processor_get_file_descriptor(
+    const rtems_bsd_arp_processor_context *ctx)
+{
+	return ctx->fd;
+}
+
+int
+rtems_bsd_arp_processor_process(
+    rtems_bsd_arp_processor_context *ctx,
+    rtems_bsd_arp_processor processor, void *arg)
+{
+	ssize_t n;
+	size_t buf_avail;
+	size_t buf_pos;
+
+	n = read(ctx->fd, &ctx->buf[0], ctx->buf_size);
+	if (n < 0) {
+		return -1;
+	}
+
+	buf_avail = (size_t) n;
+	buf_pos = 0;
+
+	while (buf_pos < buf_avail) {
+		const uint8_t *pkt = &ctx->buf[0] + buf_pos;
+		struct bpf_hdr bp;
+
+		memcpy(&bp, pkt, sizeof(bp));
+
+		if (bp.bh_caplen == bp.bh_datalen &&
+		    buf_pos + bp.bh_caplen + bp.bh_hdrlen <= buf_avail) {
+			const uint8_t *payload = pkt + bp.bh_hdrlen +
+			    ETHER_HDR_LEN;
+			size_t payload_size = bp.bh_caplen - ETHER_HDR_LEN;
+
+			process_arp_packet(payload, payload_size, ctx->fd, ctx->eaddr,
+			    processor, NULL);
+		}
+
+		buf_pos += BPF_WORDALIGN(bp.bh_hdrlen + bp.bh_caplen);
+	}
+
+	return 0;
+}