+ register struct block *b0, *b1, *b2;
+ register struct slist *s;
+
+ switch (dir) {
+ case Q_SRC:
+ /*
+ * Oh, yuk.
+ *
+ * For control frames, there is no SA.
+ *
+ * For management frames, SA is at an
+ * offset of 10 from the beginning of
+ * the packet.
+ *
+ * For data frames, SA is at an offset
+ * of 10 from the beginning of the packet
+ * if From DS is clear, at an offset of
+ * 16 from the beginning of the packet
+ * if From DS is set and To DS is clear,
+ * and an offset of 24 from the beginning
+ * of the packet if From DS is set and To DS
+ * is set.
+ */
+
+ /*
+ * Generate the tests to be done for data frames
+ * with From DS set.
+ *
+ * First, check for To DS set, i.e. check "link[1] & 0x01".
+ */
+ s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
+ s->s.k = 1;
+ b1 = new_block(JMP(BPF_JSET));
+ b1->s.k = 0x01; /* To DS */
+ b1->stmts = s;
+
+ /*
+ * If To DS is set, the SA is at 24.
+ */
+ b0 = gen_bcmp(24, 6, eaddr);
+ gen_and(b1, b0);
+
+ /*
+ * Now, check for To DS not set, i.e. check
+ * "!(link[1] & 0x01)".
+ */
+ s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
+ s->s.k = 1;
+ b2 = new_block(JMP(BPF_JSET));
+ b2->s.k = 0x01; /* To DS */
+ b2->stmts = s;
+ gen_not(b2);
+
+ /*
+ * If To DS is not set, the SA is at 16.
+ */
+ b1 = gen_bcmp(16, 6, eaddr);
+ gen_and(b2, b1);
+
+ /*
+ * Now OR together the last two checks. That gives
+ * the complete set of checks for data frames with
+ * From DS set.
+ */
+ gen_or(b1, b0);
+
+ /*
+ * Now check for From DS being set, and AND that with
+ * the ORed-together checks.
+ */
+ s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
+ s->s.k = 1;
+ b1 = new_block(JMP(BPF_JSET));
+ b1->s.k = 0x02; /* From DS */
+ b1->stmts = s;
+ gen_and(b1, b0);
+
+ /*
+ * Now check for data frames with From DS not set.
+ */
+ s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
+ s->s.k = 1;
+ b2 = new_block(JMP(BPF_JSET));
+ b2->s.k = 0x02; /* From DS */
+ b2->stmts = s;
+ gen_not(b2);
+
+ /*
+ * If From DS isn't set, the SA is at 10.
+ */
+ b1 = gen_bcmp(10, 6, eaddr);
+ gen_and(b2, b1);
+
+ /*
+ * Now OR together the checks for data frames with
+ * From DS not set and for data frames with From DS
+ * set; that gives the checks done for data frames.
+ */
+ gen_or(b1, b0);
+
+ /*
+ * Now check for a data frame.
+ * I.e, check "link[0] & 0x08".
+ */
+ s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
+ s->s.k = 0;
+ b1 = new_block(JMP(BPF_JSET));
+ b1->s.k = 0x08;
+ b1->stmts = s;
+
+ /*
+ * AND that with the checks done for data frames.
+ */
+ gen_and(b1, b0);
+
+ /*
+ * If the high-order bit of the type value is 0, this
+ * is a management frame.
+ * I.e, check "!(link[0] & 0x08)".
+ */
+ s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
+ s->s.k = 0;
+ b2 = new_block(JMP(BPF_JSET));
+ b2->s.k = 0x08;
+ b2->stmts = s;
+ gen_not(b2);
+
+ /*
+ * For management frames, the SA is at 10.
+ */
+ b1 = gen_bcmp(10, 6, eaddr);
+ gen_and(b2, b1);
+
+ /*
+ * OR that with the checks done for data frames.
+ * That gives the checks done for management and
+ * data frames.
+ */
+ gen_or(b1, b0);
+
+ /*
+ * If the low-order bit of the type value is 1,
+ * this is either a control frame or a frame
+ * with a reserved type, and thus not a
+ * frame with an SA.
+ *
+ * I.e., check "!(link[0] & 0x04)".
+ */
+ s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
+ s->s.k = 0;
+ b1 = new_block(JMP(BPF_JSET));
+ b1->s.k = 0x04;
+ b1->stmts = s;
+ gen_not(b1);
+
+ /*
+ * AND that with the checks for data and management
+ * frames.
+ */
+ gen_and(b1, b0);
+ return b0;
+
+ case Q_DST:
+ /*
+ * Oh, yuk.
+ *
+ * For control frames, there is no DA.
+ *
+ * For management frames, DA is at an
+ * offset of 4 from the beginning of
+ * the packet.
+ *
+ * For data frames, DA is at an offset
+ * of 4 from the beginning of the packet
+ * if To DS is clear and at an offset of
+ * 16 from the beginning of the packet
+ * if To DS is set.
+ */
+
+ /*
+ * Generate the tests to be done for data frames.
+ *
+ * First, check for To DS set, i.e. "link[1] & 0x01".
+ */
+ s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
+ s->s.k = 1;
+ b1 = new_block(JMP(BPF_JSET));
+ b1->s.k = 0x01; /* To DS */
+ b1->stmts = s;
+
+ /*
+ * If To DS is set, the DA is at 16.
+ */
+ b0 = gen_bcmp(16, 6, eaddr);
+ gen_and(b1, b0);
+
+ /*
+ * Now, check for To DS not set, i.e. check
+ * "!(link[1] & 0x01)".
+ */
+ s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
+ s->s.k = 1;
+ b2 = new_block(JMP(BPF_JSET));
+ b2->s.k = 0x01; /* To DS */
+ b2->stmts = s;
+ gen_not(b2);
+
+ /*
+ * If To DS is not set, the DA is at 4.
+ */
+ b1 = gen_bcmp(4, 6, eaddr);
+ gen_and(b2, b1);
+
+ /*
+ * Now OR together the last two checks. That gives
+ * the complete set of checks for data frames.
+ */
+ gen_or(b1, b0);
+
+ /*
+ * Now check for a data frame.
+ * I.e, check "link[0] & 0x08".
+ */
+ s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
+ s->s.k = 0;
+ b1 = new_block(JMP(BPF_JSET));
+ b1->s.k = 0x08;
+ b1->stmts = s;
+
+ /*
+ * AND that with the checks done for data frames.
+ */
+ gen_and(b1, b0);
+
+ /*
+ * If the high-order bit of the type value is 0, this
+ * is a management frame.
+ * I.e, check "!(link[0] & 0x08)".
+ */
+ s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
+ s->s.k = 0;
+ b2 = new_block(JMP(BPF_JSET));
+ b2->s.k = 0x08;
+ b2->stmts = s;
+ gen_not(b2);
+
+ /*
+ * For management frames, the DA is at 4.
+ */
+ b1 = gen_bcmp(4, 6, eaddr);
+ gen_and(b2, b1);
+
+ /*
+ * OR that with the checks done for data frames.
+ * That gives the checks done for management and
+ * data frames.
+ */
+ gen_or(b1, b0);
+
+ /*
+ * If the low-order bit of the type value is 1,
+ * this is either a control frame or a frame
+ * with a reserved type, and thus not a
+ * frame with an SA.
+ *
+ * I.e., check "!(link[0] & 0x04)".
+ */
+ s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
+ s->s.k = 0;
+ b1 = new_block(JMP(BPF_JSET));
+ b1->s.k = 0x04;
+ b1->stmts = s;
+ gen_not(b1);
+
+ /*
+ * AND that with the checks for data and management
+ * frames.
+ */
+ gen_and(b1, b0);
+ return b0;
+
+ case Q_AND:
+ b0 = gen_wlanhostop(eaddr, Q_SRC);
+ b1 = gen_wlanhostop(eaddr, Q_DST);
+ gen_and(b0, b1);
+ return b1;
+
+ case Q_DEFAULT:
+ case Q_OR:
+ b0 = gen_wlanhostop(eaddr, Q_SRC);
+ b1 = gen_wlanhostop(eaddr, Q_DST);
+ gen_or(b0, b1);
+ return b1;
+ }
+ abort();
+ /* NOTREACHED */
+}
+
+/*
+ * Like gen_ehostop, but for RFC 2625 IP-over-Fibre-Channel.
+ * (We assume that the addresses are IEEE 48-bit MAC addresses,
+ * as the RFC states.)
+ */
+static struct block *
+gen_ipfchostop(eaddr, dir)
+ register const u_char *eaddr;
+ register int dir;
+{
+ register struct block *b0, *b1;
+
+ switch (dir) {
+ case Q_SRC:
+ return gen_bcmp(10, 6, eaddr);
+
+ case Q_DST:
+ return gen_bcmp(2, 6, eaddr);
+
+ case Q_AND:
+ b0 = gen_ipfchostop(eaddr, Q_SRC);
+ b1 = gen_ipfchostop(eaddr, Q_DST);
+ gen_and(b0, b1);
+ return b1;
+
+ case Q_DEFAULT:
+ case Q_OR:
+ b0 = gen_ipfchostop(eaddr, Q_SRC);
+ b1 = gen_ipfchostop(eaddr, Q_DST);
+ gen_or(b0, b1);
+ return b1;
+ }
+ abort();
+ /* NOTREACHED */
+}
+
+/*
+ * This is quite tricky because there may be pad bytes in front of the
+ * DECNET header, and then there are two possible data packet formats that
+ * carry both src and dst addresses, plus 5 packet types in a format that
+ * carries only the src node, plus 2 types that use a different format and
+ * also carry just the src node.
+ *
+ * Yuck.
+ *
+ * Instead of doing those all right, we just look for data packets with
+ * 0 or 1 bytes of padding. If you want to look at other packets, that
+ * will require a lot more hacking.
+ *
+ * To add support for filtering on DECNET "areas" (network numbers)
+ * one would want to add a "mask" argument to this routine. That would
+ * make the filter even more inefficient, although one could be clever
+ * and not generate masking instructions if the mask is 0xFFFF.
+ */
+static struct block *
+gen_dnhostop(addr, dir, base_off)
+ bpf_u_int32 addr;
+ int dir;
+ u_int base_off;
+{
+ struct block *b0, *b1, *b2, *tmp;
+ u_int offset_lh; /* offset if long header is received */
+ u_int offset_sh; /* offset if short header is received */
projects / libpcap / blobdiff