Split interface and socket out into OS bpf, if-bsd and if-linux.

1 files changed, 71 insertions, 0 deletions

diff --git a/bpf-filter.h b/bpf-filter.h
new file mode 100644
index 00000000..17ba8453
--- /dev/null
+++ b/bpf-filter.h
@@ -0,0 +1,71 @@
+/*
+ * dhcpcd - DHCP client daemon
+ * Copyright 2006-2008 Roy Marples <roy@marples.name>
+ *
+ * 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.
+ */
+
+/* Credit where credit is due :)
+ * The below BPF filter is taken from ISC DHCP */
+static struct bpf_insn dhcp_bpf_filter [] = {
+	/* Make sure this is an IP packet... */
+	BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 12),
+	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, ETHERTYPE_IP, 0, 8),
+
+	/* Make sure it's a UDP packet... */
+	BPF_STMT (BPF_LD + BPF_B + BPF_ABS, 23),
+	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 0, 6),
+
+	/* Make sure this isn't a fragment... */
+	BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 20),
+	BPF_JUMP (BPF_JMP + BPF_JSET + BPF_K, 0x1fff, 4, 0),
+
+	/* Get the IP header length... */
+	BPF_STMT (BPF_LDX + BPF_B + BPF_MSH, 14),
+
+	/* Make sure it's to the right port... */
+	BPF_STMT (BPF_LD + BPF_H + BPF_IND, 16),
+	BPF_JUMP (BPF_JMP + BPF_JEQ + BPF_K, DHCP_CLIENT_PORT, 0, 1),
+
+	/* If we passed all the tests, ask for the whole packet. */
+	BPF_STMT (BPF_RET + BPF_K, ~0U),
+
+	/* Otherwise, drop it. */
+	BPF_STMT (BPF_RET + BPF_K, 0),
+};
+
+/* This, however, is mine */
+static 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 REPLY... */
+	BPF_STMT (BPF_LD + BPF_H + BPF_ABS, 20),
+	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, ~0U),
+
+	/* Otherwise, drop it. */
+	BPF_STMT (BPF_RET + BPF_K, 0),
+};