static struct block *root;
+/*
+ * Absolute offsets, which are offsets from the beginning of the raw
+ * packet data, are, in the general case, the sum of a variable value
+ * and a constant value; the variable value may be absent, in which
+ * case the offset is only the constant value, and the constant value
+ * may be zero, in which case the offset is only the variable value.
+ *
+ * bpf_abs_offset is a structure containing all that information:
+ *
+ * is_variable is 1 if there's a variable part.
+ *
+ * constant_part is the constant part of the value, possibly zero;
+ *
+ * if is_variable is 1, reg is the register number for a register
+ * containing the variable value if the register has been assigned,
+ * and -1 otherwise.
+ */
+typedef struct {
+ int is_variable;
+ u_int constant_part;
+ int reg;
+} bpf_abs_offset;
+
/*
* Value passed to gen_load_a() to indicate what the offset argument
* is relative to the beginning of.
static struct slist *gen_load_radiotap_llprefixlen(void);
static struct slist *gen_load_ppi_llprefixlen(void);
static void insert_compute_vloffsets(struct block *);
-static struct slist *gen_llprefixlen(void);
-static struct slist *gen_prevlinkhdrprefixlen(void);
-static struct slist *gen_off_linkpl(void);
+static struct slist *gen_abs_offset_varpart(bpf_abs_offset *);
static int ethertype_to_ppptype(int);
static struct block *gen_linktype(int);
static struct block *gen_snap(bpf_u_int32, bpf_u_int32);
*/
/*
- * The offset of the beginning of the link-layer payload, from the beginning
- * of the raw packet data, is, in the general case, the sum of a variable
- * value and a constant value; the variable value may be absent, in which
- * case the offset is only the constant value, and the constant value may
- * be zero, in which case the offset is only the variable value.
- *
- * off_linkhdr_constant_part is the constant value.
- *
- * reg_off_linkhdr is the register number for a register containing the
- * variable value, and -1 otherwise.
- *
- * off_linkhdr_is_variable is 1 if there's a variable part.
+ * Absolute offset of the beginning of the link-layer header.
*/
-static u_int off_linkhdr_constant_part;
-static int reg_off_linkhdr;
-static int off_linkhdr_is_variable;
+static bpf_abs_offset off_linkhdr;
/*
* If we're checking a link-layer header for a packet encapsulated in
* previous layers' link-layer header from the beginning of the raw
* packet data.
*/
-static u_int off_prevlinkhdr_constant_part;
-static int reg_off_prevlinkhdr;
-static int off_prevlinkhdr_is_variable;
+static bpf_abs_offset off_prevlinkhdr;
/*
* This is the equivalent information for the outermost layers' link-layer
* header.
*/
-static u_int off_outermostlinkhdr_constant_part;
-static int reg_off_outermostlinkhdr;
-static int off_outermostlinkhdr_is_variable;
+static bpf_abs_offset off_outermostlinkhdr;
/*
- * The offset of the beginning of the link-layer payload, from the beginning
- * of the raw packet data, is, in the general case, the sum of a variable
- * value and a constant value; the variable value may be absent, in which
- * case the offset is only the constant value, and the constant value may
- * be zero, in which case the offset is only the variable value.
- *
- * off_linkpl_constant_part is the constant value.
- *
- * reg_off_linkpl is the register number for a register containing the
- * variable value, and -1 otherwise.
- *
- * off_linkpl_is_variable is 1 if there's a variable part.
+ * "Push" the current value of the link-layer header type and link-layer
+ * header offset onto a "stack", and set a new value. (It's not a
+ * full-blown stack; we keep only the top two items.)
+ */
+#define PUSH_LINKHDR(new_linktype, new_is_variable, new_constant_part, new_reg) \
+{ \
+ prevlinktype = new_linktype; \
+ off_prevlinkhdr = off_linkhdr; \
+ linktype = new_linktype; \
+ off_linkhdr.is_variable = new_is_variable; \
+ off_linkhdr.constant_part = new_constant_part; \
+ off_linkhdr.reg = new_reg; \
+}
+
+/*
+ * Absolute offset of the beginning of the link-layer payload.
*/
-static u_int off_linkpl_constant_part;
-static int off_linkpl_is_variable;
-static int reg_off_linkpl;
+static bpf_abs_offset off_linkpl;
/*
* "off_linktype" is the offset to information in the link-layer header
* giving the packet type. This offset is relative to the beginning
- * of the link-layer header - i.e., it doesn't include off_linkhdr_constant_part - so
+ * of the link-layer header - i.e., it doesn't include off_linkhdr.constant_part - so
* loads with an offset that includes "off_linktype" should use
* OR_LINKHDR.
*
/*
* These are offsets to the beginning of the network-layer header.
* They are relative to the beginning of the link-layer payload (i.e.,
- * they don't include off_linkhdr_constant_part or off_linkpl_constant_part).
+ * they don't include off_linkhdr.constant_part or off_linkpl.constant_part).
*
* If the link layer never uses 802.2 LLC:
*
* We start out with only one link-layer header.
*/
outermostlinktype = pcap_datalink(p);
- off_outermostlinkhdr_constant_part = 0;
- off_outermostlinkhdr_is_variable = 0;
- reg_off_outermostlinkhdr = -1;
+ off_outermostlinkhdr.constant_part = 0;
+ off_outermostlinkhdr.is_variable = 0;
+ off_outermostlinkhdr.reg = -1;
prevlinktype = outermostlinktype;
- off_prevlinkhdr_constant_part = 0;
- off_prevlinkhdr_is_variable = 0;
- reg_off_prevlinkhdr = -1;
+ off_prevlinkhdr.constant_part = 0;
+ off_prevlinkhdr.is_variable = 0;
+ off_prevlinkhdr.reg = -1;
linktype = outermostlinktype;
- off_linkhdr_constant_part = 0;
- off_linkhdr_is_variable = 0;
- reg_off_linkhdr = -1;
+ off_linkhdr.constant_part = 0;
+ off_linkhdr.is_variable = 0;
+ off_linkhdr.reg = -1;
/*
* XXX
*/
- off_linkpl_constant_part = 0;
- off_linkpl_is_variable = 0;
- reg_off_linkpl = -1;
+ off_linkpl.constant_part = 0;
+ off_linkpl.is_variable = 0;
+ off_linkpl.reg = -1;
/*
* Assume it's not raw ATM with a pseudo-header, for now.
case DLT_ARCNET:
off_linktype = 2;
- off_linkpl_constant_part = 6;
+ off_linkpl.constant_part = 6;
off_nl = 0; /* XXX in reality, variable! */
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_ARCNET_LINUX:
off_linktype = 4;
- off_linkpl_constant_part = 8;
+ off_linkpl.constant_part = 8;
off_nl = 0; /* XXX in reality, variable! */
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_EN10MB:
off_linktype = 12;
- off_linkpl_constant_part = 14; /* Ethernet header length */
+ off_linkpl.constant_part = 14; /* Ethernet header length */
off_nl = 0; /* Ethernet II */
off_nl_nosnap = 3; /* 802.3+802.2 */
return;
* header is hacked into our SLIP driver.
*/
off_linktype = -1;
- off_linkpl_constant_part = 16;
+ off_linkpl.constant_part = 16;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
/* XXX this may be the same as the DLT_PPP_BSDOS case */
off_linktype = -1;
/* XXX end */
- off_linkpl_constant_part = 24;
+ off_linkpl.constant_part = 24;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_NULL:
case DLT_LOOP:
off_linktype = 0;
- off_linkpl_constant_part = 4;
+ off_linkpl.constant_part = 4;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_ENC:
off_linktype = 0;
- off_linkpl_constant_part = 12;
+ off_linkpl.constant_part = 12;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_C_HDLC: /* BSD/OS Cisco HDLC */
case DLT_PPP_SERIAL: /* NetBSD sync/async serial PPP */
off_linktype = 2; /* skip HDLC-like framing */
- off_linkpl_constant_part = 4; /* skip HDLC-like framing and protocol field */
+ off_linkpl.constant_part = 4; /* skip HDLC-like framing and protocol field */
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
* only covers session state.
*/
off_linktype = 6;
- off_linkpl_constant_part = 8;
+ off_linkpl.constant_part = 8;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_PPP_BSDOS:
off_linktype = 5;
- off_linkpl_constant_part = 24;
+ off_linkpl.constant_part = 24;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
*/
off_linktype = 13;
off_linktype += pcap_fddipad;
- off_linkpl_constant_part = 13; /* FDDI MAC header length */
- off_linkpl_constant_part += pcap_fddipad;
+ off_linkpl.constant_part = 13; /* FDDI MAC header length */
+ off_linkpl.constant_part += pcap_fddipad;
off_nl = 8; /* 802.2+SNAP */
off_nl_nosnap = 3; /* 802.2 */
return;
* 8 - figure out which byte that is).
*/
off_linktype = 14;
- off_linkpl_constant_part = 14; /* Token Ring MAC header length */
+ off_linkpl.constant_part = 14; /* Token Ring MAC header length */
off_nl = 8; /* 802.2+SNAP */
off_nl_nosnap = 3; /* 802.2 */
return;
* variable-length.
*/
off_linktype = 24;
- off_linkpl_constant_part = 0; /* link-layer header is variable-length */
- off_linkpl_is_variable = 1;
+ off_linkpl.constant_part = 0; /* link-layer header is variable-length */
+ off_linkpl.is_variable = 1;
off_nl = 8; /* 802.2+SNAP */
off_nl_nosnap = 3; /* 802.2 */
return;
* generate code to check for this too.
*/
off_linktype = 24;
- off_linkpl_constant_part = 0; /* link-layer header is variable-length */
- off_linkpl_is_variable = 1;
+ off_linkpl.constant_part = 0; /* link-layer header is variable-length */
+ off_linkpl.is_variable = 1;
off_nl = 8; /* 802.2+SNAP */
off_nl_nosnap = 3; /* 802.2 */
return;
* PPPo{A,E} and a PPP protocol of IP and....
*/
off_linktype = 0;
- off_linkpl_constant_part = 0; /* packet begins with LLC header */
+ off_linkpl.constant_part = 0; /* packet begins with LLC header */
off_nl = 8; /* 802.2+SNAP */
off_nl_nosnap = 3; /* 802.2 */
return;
off_proto = PROTO_POS;
off_payload = SUNATM_PKT_BEGIN_POS;
off_linktype = off_payload;
- off_linkpl_constant_part = off_payload; /* if LLC-encapsulated */
+ off_linkpl.constant_part = off_payload; /* if LLC-encapsulated */
off_nl = 8; /* 802.2+SNAP */
off_nl_nosnap = 3; /* 802.2 */
return;
case DLT_IPV4:
case DLT_IPV6:
off_linktype = -1;
- off_linkpl_constant_part = 0;
+ off_linkpl.constant_part = 0;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_LINUX_SLL: /* fake header for Linux cooked socket */
off_linktype = 14;
- off_linkpl_constant_part = 16;
+ off_linkpl.constant_part = 16;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
* "long" DDP packet following.
*/
off_linktype = -1;
- off_linkpl_constant_part = 0;
+ off_linkpl.constant_part = 0;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
* 2625 says SNAP should be used.
*/
off_linktype = 16;
- off_linkpl_constant_part = 16;
+ off_linkpl.constant_part = 16;
off_nl = 8; /* 802.2+SNAP */
off_nl_nosnap = 3; /* 802.2 */
return;
* frames (NLPID of 0x80).
*/
off_linktype = -1;
- off_linkpl_constant_part = 0;
+ off_linkpl.constant_part = 0;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
*/
case DLT_MFR:
off_linktype = -1;
- off_linkpl_constant_part = 0;
+ off_linkpl.constant_part = 0;
off_nl = 4;
off_nl_nosnap = 0; /* XXX - for now -> no 802.2 LLC */
return;
case DLT_APPLE_IP_OVER_IEEE1394:
off_linktype = 16;
- off_linkpl_constant_part = 18;
+ off_linkpl.constant_part = 18;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_SYMANTEC_FIREWALL:
off_linktype = 6;
- off_linkpl_constant_part = 44;
+ off_linkpl.constant_part = 44;
off_nl = 0; /* Ethernet II */
off_nl_nosnap = 0; /* XXX - what does it do with 802.3 packets? */
return;
#ifdef HAVE_NET_PFVAR_H
case DLT_PFLOG:
off_linktype = 0;
- off_linkpl_constant_part = PFLOG_HDRLEN;
+ off_linkpl.constant_part = PFLOG_HDRLEN;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
return;
case DLT_JUNIPER_CHDLC:
case DLT_JUNIPER_FRELAY:
off_linktype = 4;
- off_linkpl_constant_part = 4;
+ off_linkpl.constant_part = 4;
off_nl = 0;
off_nl_nosnap = -1; /* no 802.2 LLC */
return;
case DLT_JUNIPER_ATM1:
off_linktype = 4; /* in reality variable between 4-8 */
- off_linkpl_constant_part = 4; /* in reality variable between 4-8 */
+ off_linkpl.constant_part = 4; /* in reality variable between 4-8 */
off_nl = 0;
off_nl_nosnap = 10;
return;
case DLT_JUNIPER_ATM2:
off_linktype = 8; /* in reality variable between 8-12 */
- off_linkpl_constant_part = 8; /* in reality variable between 8-12 */
+ off_linkpl.constant_part = 8; /* in reality variable between 8-12 */
off_nl = 0;
off_nl_nosnap = 10;
return;
* contain raw ethernet frames */
case DLT_JUNIPER_PPPOE:
case DLT_JUNIPER_ETHER:
- off_linkpl_constant_part = 14;
+ off_linkpl.constant_part = 14;
off_linktype = 16;
off_nl = 18; /* Ethernet II */
off_nl_nosnap = 21; /* 802.3+802.2 */
case DLT_JUNIPER_PPPOE_ATM:
off_linktype = 4;
- off_linkpl_constant_part = 6;
+ off_linkpl.constant_part = 6;
off_nl = 0;
off_nl_nosnap = -1; /* no 802.2 LLC */
return;
case DLT_JUNIPER_GGSN:
off_linktype = 6;
- off_linkpl_constant_part = 12;
+ off_linkpl.constant_part = 12;
off_nl = 0;
off_nl_nosnap = -1; /* no 802.2 LLC */
return;
case DLT_JUNIPER_ES:
off_linktype = 6;
- off_linkpl_constant_part = -1; /* not really a network layer but raw IP addresses */
+ off_linkpl.constant_part = -1; /* not really a network layer but raw IP addresses */
off_nl = -1; /* not really a network layer but raw IP addresses */
off_nl_nosnap = -1; /* no 802.2 LLC */
return;
case DLT_JUNIPER_MONITOR:
off_linktype = 12;
- off_linkpl_constant_part = 12;
+ off_linkpl.constant_part = 12;
off_nl = 0; /* raw IP/IP6 header */
off_nl_nosnap = -1; /* no 802.2 LLC */
return;
case DLT_BACNET_MS_TP:
off_linktype = -1;
- off_linkpl_constant_part = -1;
+ off_linkpl.constant_part = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
case DLT_JUNIPER_SERVICES:
off_linktype = 12;
- off_linkpl_constant_part = -1; /* L3 proto location dep. on cookie type */
+ off_linkpl.constant_part = -1; /* L3 proto location dep. on cookie type */
off_nl = -1; /* L3 proto location dep. on cookie type */
off_nl_nosnap = -1; /* no 802.2 LLC */
return;
case DLT_JUNIPER_VP:
off_linktype = 18;
- off_linkpl_constant_part = -1;
+ off_linkpl.constant_part = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
case DLT_JUNIPER_ST:
off_linktype = 18;
- off_linkpl_constant_part = -1;
+ off_linkpl.constant_part = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
case DLT_JUNIPER_ISM:
off_linktype = 8;
- off_linkpl_constant_part = -1;
+ off_linkpl.constant_part = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
case DLT_JUNIPER_FIBRECHANNEL:
case DLT_JUNIPER_ATM_CEMIC:
off_linktype = 8;
- off_linkpl_constant_part = -1;
+ off_linkpl.constant_part = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
off_dpc = 4;
off_sls = 7;
off_linktype = -1;
- off_linkpl_constant_part = -1;
+ off_linkpl.constant_part = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
off_dpc = 8;
off_sls = 11;
off_linktype = -1;
- off_linkpl_constant_part = -1;
+ off_linkpl.constant_part = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
off_dpc = 24;
off_sls = 27;
off_linktype = -1;
- off_linkpl_constant_part = -1;
+ off_linkpl.constant_part = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
case DLT_PFSYNC:
off_linktype = -1;
- off_linkpl_constant_part = 4;
+ off_linkpl.constant_part = 4;
off_nl = 0;
off_nl_nosnap = 0;
return;
* Currently, only raw "link[N:M]" filtering is supported.
*/
off_linktype = -1; /* variable, min 15, max 71 steps of 7 */
- off_linkpl_constant_part = -1;
+ off_linkpl.constant_part = -1;
off_nl = -1; /* variable, min 16, max 71 steps of 7 */
off_nl_nosnap = -1; /* no 802.2 LLC */
return;
case DLT_IPNET:
off_linktype = 1;
- off_linkpl_constant_part = 24; /* ipnet header length */
+ off_linkpl.constant_part = 24; /* ipnet header length */
off_nl = 0;
off_nl_nosnap = -1;
return;
case DLT_NETANALYZER:
- off_linkhdr_constant_part = 4; /* Ethernet header is past 4-byte pseudo-header */
+ off_linkhdr.constant_part = 4; /* Ethernet header is past 4-byte pseudo-header */
off_linktype = 12;
- off_linkpl_constant_part = off_linkhdr_constant_part + 14; /* pseudo-header+Ethernet header length */
+ off_linkpl.constant_part = off_linkhdr.constant_part + 14; /* pseudo-header+Ethernet header length */
off_nl = 0; /* Ethernet II */
off_nl_nosnap = 3; /* 802.3+802.2 */
return;
case DLT_NETANALYZER_TRANSPARENT:
- off_linkhdr_constant_part = 12; /* MAC header is past 4-byte pseudo-header, preamble, and SFD */
+ off_linkhdr.constant_part = 12; /* MAC header is past 4-byte pseudo-header, preamble, and SFD */
off_linktype = 12;
- off_linkpl_constant_part = off_linkhdr_constant_part + 14; /* pseudo-header+preamble+SFD+Ethernet header length */
+ off_linkpl.constant_part = off_linkhdr.constant_part + 14; /* pseudo-header+preamble+SFD+Ethernet header length */
off_nl = 0; /* Ethernet II */
off_nl_nosnap = 3; /* 802.3+802.2 */
return;
if (linktype >= DLT_MATCHING_MIN &&
linktype <= DLT_MATCHING_MAX) {
off_linktype = -1;
- off_linkpl_constant_part = -1;
+ off_linkpl.constant_part = -1;
off_nl = -1;
off_nl_nosnap = -1;
return;
{
struct slist *s, *s2;
- s = gen_llprefixlen();
+ s = gen_abs_offset_varpart(&off_linkhdr);
/*
* If "s" is non-null, it has code to arrange that the X register
* header.
*
* Otherwise, the length of the prefix preceding the link-layer
- * header is "off_linkhdr_constant_part".
+ * header is "off_linkhdr.constant_part".
*/
if (s != NULL) {
/*
* do an indirect load, to use the X register as an offset.
*/
s2 = new_stmt(BPF_LD|BPF_IND|size);
- s2->s.k = off_linkhdr_constant_part + offset;
+ s2->s.k = off_linkhdr.constant_part + offset;
sappend(s, s2);
} else {
/*
* There is no variable-length header preceding the
- * link-layer header; add in off_linkhdr_constant_part, which, if
+ * link-layer header; add in off_linkhdr.constant_part, which, if
* there's a fixed-length header preceding the
* link-layer header, is the length of that header.
*/
s = new_stmt(BPF_LD|BPF_ABS|size);
- s->s.k = off_linkhdr_constant_part + offset;
+ s->s.k = off_linkhdr.constant_part + offset;
}
return s;
}
{
struct slist *s, *s2;
- s = gen_prevlinkhdrprefixlen();
+ s = gen_abs_offset_varpart(&off_prevlinkhdr);
/*
* If "s" is non-null, it has code to arrange that the X register
* header.
*
* Otherwise, the length of the prefix preceding the link-layer
- * header is "off_prevlinkhdr_constant_part".
+ * header is "off_prevlinkhdr.constant_part".
*/
if (s != NULL) {
/*
* do an indirect load, to use the X register as an offset.
*/
s2 = new_stmt(BPF_LD|BPF_IND|size);
- s2->s.k = off_prevlinkhdr_constant_part + offset;
+ s2->s.k = off_prevlinkhdr.constant_part + offset;
sappend(s, s2);
} else {
/*
* There is no variable-length header preceding the
- * link-layer header; add in off_prevlinkhdr_constant_part, which,
+ * link-layer header; add in off_prevlinkhdr.constant_part, which,
* if there's a fixed-length header preceding the
* link-layer header, is the length of that header.
*/
s = new_stmt(BPF_LD|BPF_ABS|size);
- s->s.k = off_prevlinkhdr_constant_part + offset;
+ s->s.k = off_prevlinkhdr.constant_part + offset;
}
return s;
}
{
struct slist *s, *s2;
- s = gen_off_linkpl();
+ s = gen_abs_offset_varpart(&off_linkpl);
/*
* If s is non-null, the offset of the link-layer payload is
* variable, and s points to a list of instructions that
* arrange that the X register contains the variable part
* of that offset. The sum of that variable part and
- * off_linkpl_constant_part is the offset.
+ * off_linkpl.constant_part is the offset.
*
* Otherwise, the offset of the link-layer payload is constant,
- * and is in off_linkpl_constant_part.
+ * and is in off_linkpl.constant_part.
*/
if (s != NULL) {
/*
* register as part of the offset of the load.
*/
s2 = new_stmt(BPF_LD|BPF_IND|size);
- s2->s.k = off_linkpl_constant_part + offset;
+ s2->s.k = off_linkpl.constant_part + offset;
sappend(s, s2);
} else {
/*
* The offset of the link-layer payload is constant,
- * and is in off_linkpl_constant_part; load the value
+ * and is in off_linkpl.constant_part; load the value
* at that offset plus the specified offset.
*/
s = new_stmt(BPF_LD|BPF_ABS|size);
- s->s.k = off_linkpl_constant_part + offset;
+ s->s.k = off_linkpl.constant_part + offset;
}
return s;
}
* part in the offset of the load.
*/
s2 = new_stmt(BPF_LD|BPF_IND|size);
- s2->s.k = off_linkpl_constant_part + off_nl + offset;
+ s2->s.k = off_linkpl.constant_part + off_nl + offset;
sappend(s, s2);
break;
{
struct slist *s, *s2;
- s = gen_off_linkpl();
+ s = gen_abs_offset_varpart(&off_linkpl);
if (s != NULL) {
/*
* The offset of the link-layer payload has a variable
* mode. Load the length of the IPv4 header, which
* is at an offset of off_nl from the beginning of
* the link-layer payload, and thus at an offset of
- * off_linkpl_constant_part + off_nl from the beginning
+ * off_linkpl.constant_part + off_nl from the beginning
* of the raw packet data, using that addressing mode.
*/
s = new_stmt(BPF_LDX|BPF_MSH|BPF_B);
- s->s.k = off_linkpl_constant_part + off_nl;
+ s->s.k = off_linkpl.constant_part + off_nl;
}
return s;
}
*/
b0 = gen_cmp(OR_LINKHDR, off_linktype, BPF_H,
LINUX_SLL_P_802_2);
- b1 = gen_cmp(OR_LINKHDR, off_linkpl_constant_part, BPF_B,
+ b1 = gen_cmp(OR_LINKHDR, off_linkpl.constant_part, BPF_B,
(bpf_int32)proto);
gen_and(b0, b1);
return b1;
* but no known software generates headers that aren't 144
* bytes long.
*/
- if (reg_off_linkhdr != -1) {
+ if (off_linkhdr.reg != -1) {
/*
* Load the cookie.
*/
* loading the length of the AVS header.
*/
s2 = new_stmt(BPF_ST);
- s2->s.k = reg_off_linkhdr;
+ s2->s.k = off_linkhdr.reg;
sappend(s1, s2);
sjcommon->s.jf = s2;
* generated uses that prefix, so we don't need to generate any
* code to load it.)
*/
- if (reg_off_linkhdr != -1) {
+ if (off_linkhdr.reg != -1) {
/*
* The 4 bytes at an offset of 4 from the beginning of
* the AVS header are the length of the AVS header.
* it.
*/
s2 = new_stmt(BPF_ST);
- s2->s.k = reg_off_linkhdr;
+ s2->s.k = off_linkhdr.reg;
sappend(s1, s2);
/*
* generated uses that prefix, so we don't need to generate any
* code to load it.)
*/
- if (reg_off_linkhdr != -1) {
+ if (off_linkhdr.reg != -1) {
/*
* The 2 bytes at offsets of 2 and 3 from the beginning
* of the radiotap header are the length of the radiotap
* it.
*/
s2 = new_stmt(BPF_ST);
- s2->s.k = reg_off_linkhdr;
+ s2->s.k = off_linkhdr.reg;
sappend(s1, s2);
/*
* into the register assigned to hold that length, if one has
* been assigned.
*/
- if (reg_off_linkhdr != -1) {
+ if (off_linkhdr.reg != -1) {
/*
* The 2 bytes at offsets of 2 and 3 from the beginning
* of the radiotap header are the length of the radiotap
* it.
*/
s2 = new_stmt(BPF_ST);
- s2->s.k = reg_off_linkhdr;
+ s2->s.k = off_linkhdr.reg;
sappend(s1, s2);
/*
struct slist *sjset_tsft_datapad, *sjset_notsft_datapad;
struct slist *s_roundup;
- if (reg_off_linkpl == -1) {
+ if (off_linkpl.reg == -1) {
/*
* No register has been assigned to the offset of
* the link-layer payload, which means nobody needs
* header.
*
* Otherwise, the length of the prefix preceding the link-layer
- * header is "off_outermostlinkhdr_constant_part".
+ * header is "off_outermostlinkhdr.constant_part".
*/
if (s == NULL) {
/*
*
* Load the length of the fixed-length prefix preceding
* the link-layer header (if any) into the X register,
- * and store it in the reg_off_linkpl register.
- * That length is off_outermostlinkhdr_constant_part.
+ * and store it in the off_linkpl.reg register.
+ * That length is off_outermostlinkhdr.constant_part.
*/
s = new_stmt(BPF_LDX|BPF_IMM);
- s->s.k = off_outermostlinkhdr_constant_part;
+ s->s.k = off_outermostlinkhdr.constant_part;
}
/*
* The X register contains the offset of the beginning of the
* link-layer header; add 24, which is the minimum length
* of the MAC header for a data frame, to that, and store it
- * in reg_off_linkpl, and then load the Frame Control field,
+ * in off_linkpl.reg, and then load the Frame Control field,
* which is at the offset in the X register, with an indexed load.
*/
s2 = new_stmt(BPF_MISC|BPF_TXA);
s2->s.k = 24;
sappend(s, s2);
s2 = new_stmt(BPF_ST);
- s2->s.k = reg_off_linkpl;
+ s2->s.k = off_linkpl.reg;
sappend(s, s2);
s2 = new_stmt(BPF_LD|BPF_IND|BPF_B);
sappend(s, sjset_qos);
/*
- * If it's set, add 2 to reg_off_linkpl, to skip the QoS
+ * If it's set, add 2 to off_linkpl.reg, to skip the QoS
* field.
* Otherwise, go to the first statement of the rest of the
* program.
*/
sjset_qos->s.jt = s2 = new_stmt(BPF_LD|BPF_MEM);
- s2->s.k = reg_off_linkpl;
+ s2->s.k = off_linkpl.reg;
sappend(s, s2);
s2 = new_stmt(BPF_ALU|BPF_ADD|BPF_IMM);
s2->s.k = 2;
sappend(s, s2);
s2 = new_stmt(BPF_ST);
- s2->s.k = reg_off_linkpl;
+ s2->s.k = off_linkpl.reg;
sappend(s, s2);
/*
* ANDing with ~3.
*/
s_roundup = new_stmt(BPF_LD|BPF_MEM);
- s_roundup->s.k = reg_off_linkpl;
+ s_roundup->s.k = off_linkpl.reg;
sappend(s, s_roundup);
s2 = new_stmt(BPF_ALU|BPF_ADD|BPF_IMM);
s2->s.k = 3;
s2->s.k = ~3;
sappend(s, s2);
s2 = new_stmt(BPF_ST);
- s2->s.k = reg_off_linkpl;
+ s2->s.k = off_linkpl.reg;
sappend(s, s2);
sjset_tsft_datapad->s.jt = s_roundup;
}
/*
- * Generate code to load the register containing the variable part of
- * the offset of the link-layer header into the X register; if no
- * register for that offset has been allocated, allocate it first.
+ * Take an absolute offset, and:
+ *
+ * if it has no variable part, return NULL;
+ *
+ * if it has a variable part, generate code to load the register
+ * containing that variable part into the X register, returning
+ * a pointer to that code - if no register for that offset has
+ * been allocated, allocate it first.
+ *
* (The code to set that register will be generated later, but will
* be placed earlier in the code sequence.)
*/
static struct slist *
-gen_llprefixlen(void)
+gen_abs_offset_varpart(bpf_abs_offset *off)
{
struct slist *s;
- if (off_linkhdr_is_variable) {
- if (reg_off_linkhdr == -1) {
+ if (off->is_variable) {
+ if (off->reg == -1) {
/*
* We haven't yet assigned a register for the
* variable part of the offset of the link-layer
* header; allocate one.
*/
- reg_off_linkhdr = alloc_reg();
+ off->reg = alloc_reg();
}
/*
* offset of the link-layer header into the X register.
*/
s = new_stmt(BPF_LDX|BPF_MEM);
- s->s.k = reg_off_linkhdr;
- return s;
- } else {
- /*
- * That offset isn't variable, there's no variable part,
- * so we don't need to generate any code.
- */
- return NULL;
- }
-}
-
-/*
- * Generate code to compute the previous link-layer header length, if necessary,
- * putting it into the X register, and to return either a pointer to a
- * "struct slist" for the list of statements in that code, or NULL if
- * no code is necessary.
- */
-static struct slist *
-gen_prevlinkhdrprefixlen(void)
-{
- struct slist *s;
-
- if (off_prevlinkhdr_is_variable) {
- if (reg_off_prevlinkhdr == -1) {
- /*
- * We haven't yet assigned a register for the
- * variable part of the offset of the link-layer
- * header; allocate one.
- */
- reg_off_prevlinkhdr = alloc_reg();
- }
-
- /*
- * Load the register containing the variable part of the
- * offset of the link-layer header into the X register.
- */
- s = new_stmt(BPF_LDX|BPF_MEM);
- s->s.k = reg_off_prevlinkhdr;
- return s;
- } else {
- /*
- * That offset isn't variable, there's no variable part,
- * so we don't need to generate any code.
- */
- return NULL;
- }
-}
-
-/*
- * Generate code to load the register containing the variable part of
- * the offset of the link-layer payload into the X register; if no
- * register for that offset has been allocated, allocate it first.
- * (The code to set that register will be generated later, but will
- * be placed earlier in the code sequence.)
- */
-static struct slist *
-gen_off_linkpl(void)
-{
- struct slist *s;
-
- if (off_linkpl_is_variable) {
- if (reg_off_linkpl == -1) {
- /*
- * We haven't yet assigned a register for the
- * variable part of the offset of the link-layer
- * payload; allocate one.
- */
- reg_off_linkpl = alloc_reg();
- }
-
- /*
- * Load the register containing the variable part of the
- * offset of the link-layer payload into the X register.
- */
- s = new_stmt(BPF_LDX|BPF_MEM);
- s->s.k = reg_off_linkpl;
+ s->s.k = off->reg;
return s;
} else {
/*
/* A = ip->ip_p */
s[i] = new_stmt(BPF_LD|BPF_ABS|BPF_B);
- s[i]->s.k = off_linkpl_constant_part + off_nl + 9;
+ s[i]->s.k = off_linkpl.constant_part + off_nl + 9;
i++;
/* X = ip->ip_hl << 2 */
s[i] = new_stmt(BPF_LDX|BPF_MSH|BPF_B);
- s[i]->s.k = off_linkpl_constant_part + off_nl;
+ s[i]->s.k = off_linkpl.constant_part + off_nl;
i++;
break;
/* A = ip6->ip_nxt */
s[i] = new_stmt(BPF_LD|BPF_ABS|BPF_B);
- s[i]->s.k = off_linkpl_constant_part + off_nl + 6;
+ s[i]->s.k = off_linkpl.constant_part + off_nl + 6;
i++;
/* X = sizeof(struct ip6_hdr) */
s[i] = new_stmt(BPF_LDX|BPF_IMM);
*/
/* A = P[X + packet head] */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
- s[i]->s.k = off_linkpl_constant_part + off_nl;
+ s[i]->s.k = off_linkpl.constant_part + off_nl;
i++;
/* MEM[reg2] = A */
s[i] = new_stmt(BPF_ST);
i++;
/* A = P[X + packet head + 1]; */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
- s[i]->s.k = off_linkpl_constant_part + off_nl + 1;
+ s[i]->s.k = off_linkpl.constant_part + off_nl + 1;
i++;
/* A += 1 */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
i++;
/* A = P[X + packet head]; */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
- s[i]->s.k = off_linkpl_constant_part + off_nl;
+ s[i]->s.k = off_linkpl.constant_part + off_nl;
i++;
/* MEM[reg2] = A */
s[i] = new_stmt(BPF_ST);
i++;
/* A = P[X + packet head] */
s[i] = new_stmt(BPF_LD|BPF_IND|BPF_B);
- s[i]->s.k = off_linkpl_constant_part + off_nl;
+ s[i]->s.k = off_linkpl.constant_part + off_nl;
i++;
/* A += 2 */
s[i] = new_stmt(BPF_ALU|BPF_ADD|BPF_K);
* frame, so that 0 refers, for Ethernet LANE, to
* the beginning of the destination address?
*/
- s = gen_llprefixlen();
+ s = gen_abs_offset_varpart(&off_linkhdr);
/*
* If "s" is non-null, it has code to arrange that the
* into the X register and then added to the index).
*/
tmp = new_stmt(BPF_LD|BPF_IND|size);
- tmp->s.k = off_linkhdr_constant_part;
+ tmp->s.k = off_linkhdr.constant_part;
sappend(s, tmp);
sappend(inst->s, s);
break;
* XXX - are there any cases where we want
* off_nl_nosnap?
*/
- s = gen_off_linkpl();
+ s = gen_abs_offset_varpart(&off_linkpl);
/*
* If "s" is non-null, it has code to arrange that the
* start of the link-layer payload.
*/
tmp = new_stmt(BPF_LD|BPF_IND|size);
- tmp->s.k = off_linkpl_constant_part + off_nl;
+ tmp->s.k = off_linkpl.constant_part + off_nl;
sappend(s, tmp);
sappend(inst->s, s);
sappend(s, new_stmt(BPF_ALU|BPF_ADD|BPF_X));
sappend(s, new_stmt(BPF_MISC|BPF_TAX));
sappend(s, tmp = new_stmt(BPF_LD|BPF_IND|size));
- tmp->s.k = off_linkpl_constant_part + off_nl;
+ tmp->s.k = off_linkpl.constant_part + off_nl;
sappend(inst->s, s);
/*
* The payload follows the full header, including the
* VLAN tags, so skip past this VLAN tag.
*/
- off_linkpl_constant_part += 4;
+ off_linkpl.constant_part += 4;
/*
* The link-layer type information follows the VLAN tags, so
* link-layer payload, including any 802.2 LLC header, so
* it's 6 bytes past off_nl.
*/
- prevlinktype = linktype;
- off_prevlinkhdr_constant_part = off_linkhdr_constant_part;
- off_prevlinkhdr_is_variable = off_linkhdr_is_variable;
- reg_off_prevlinkhdr = reg_off_linkhdr;
-
- linktype = DLT_PPP;
- off_linkhdr_constant_part = off_linkpl_constant_part + off_nl + 6; /* 6 bytes past the PPPoE header */
- reg_off_linkhdr = reg_off_linkpl;
- off_linkhdr_is_variable = off_linkpl_is_variable;
+ PUSH_LINKHDR(DLT_PPP, off_linkpl.is_variable,
+ off_linkpl.constant_part + off_nl + 6, /* 6 bytes past the PPPoE header */
+ off_linkpl.reg);
off_linktype = 0;
- off_linkpl_constant_part = off_linkhdr_constant_part + 2;
+ off_linkpl.constant_part = off_linkhdr.constant_part + 2;
off_nl = 0;
off_nl_nosnap = 0; /* no 802.2 LLC */
*
* We assume LANE means Ethernet, not Token Ring.
*/
- prevlinktype = linktype;
- off_prevlinkhdr_constant_part = off_linkhdr_constant_part;
- off_prevlinkhdr_is_variable = off_linkhdr_is_variable;
- reg_off_prevlinkhdr = reg_off_linkhdr;
- linktype = DLT_EN10MB;
- off_linkhdr_constant_part = off_payload + 2; /* Ethernet header */
+ PUSH_LINKHDR(DLT_EN10MB, 0,
+ off_payload + 2, /* Ethernet header */
+ -1);
off_linktype = 12;
- off_linkpl_constant_part = off_linkhdr_constant_part + 14; /* Ethernet */
+ off_linkpl.constant_part = off_linkhdr.constant_part + 14; /* Ethernet */
off_nl = 0; /* Ethernet II */
off_nl_nosnap = 3; /* 802.3+802.2 */
break;
projects / libpcap / blobdiff