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DRAFT: Factor gen_host46_byname() out. #1519

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DRAFT: Factor gen_host46_byname() out. #1519

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5acbaa8
Use inet_pton() in gen_mcode6().
infrastation Apr 26, 2025
c137f6d
Rename a variable in dqkw() for consistency.
infrastation Apr 26, 2025
b927be2
WIP: Simplify gen_gateway().
infrastation Apr 28, 2025
3ae4822
WIP: Factor gen_host46_byname() out. [skip ci]
infrastation May 22, 2025
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221 changes: 86 additions & 135 deletions gencode.c
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Original file line number Diff line number Diff line change
Expand Up @@ -680,8 +680,9 @@ static struct block *gen_host(compiler_state_t *, bpf_u_int32, bpf_u_int32,
int, int, int);
static struct block *gen_host6(compiler_state_t *, struct in6_addr *,
struct in6_addr *, int, int, int);
static struct block *gen_gateway(compiler_state_t *, const char *,
struct addrinfo *, int);
static struct block *gen_host46_byname(compiler_state_t *, const char *,
const u_char, const u_char, const u_char);
static struct block *gen_gateway(compiler_state_t *, const char *, const int);
static struct block *gen_ip_proto(compiler_state_t *, const uint8_t);
static struct block *gen_ip6_proto(compiler_state_t *, const uint8_t);
static struct block *gen_ipfrag(compiler_state_t *);
Expand Down Expand Up @@ -935,7 +936,7 @@ pqkw(const unsigned id)
static const char *
dqkw(const unsigned id)
{
const char * map[] = {
const char * tokens[] = {
[Q_SRC] = "src",
[Q_DST] = "dst",
[Q_OR] = "src or dst",
Expand All @@ -947,7 +948,7 @@ dqkw(const unsigned id)
[Q_RA] = "ra",
[Q_TA] = "ta",
};
return qual2kw("dir", id, map, sizeof(map) / sizeof(map[0]));
return qual2kw("dir", id, tokens, sizeof(tokens) / sizeof(tokens[0]));
}

// ATM keywords
Expand Down Expand Up @@ -1054,6 +1055,7 @@ assert_maxval(compiler_state_t *cstate, const char *name,
#define ERRSTR_802_11_ONLY_KW "'%s' is valid for 802.11 syntax only"
#define ERRSTR_INVALID_QUAL "'%s' is not a valid qualifier for '%s'"
#define ERRSTR_UNKNOWN_MAC48HOST "unknown Ethernet-like host '%s'"
#define ERRSTR_UNKNOWN_HOST "unknown host '%s'"

// Validate a port/portrange proto qualifier and map to an IP protocol number.
static int
Expand Down Expand Up @@ -5192,6 +5194,55 @@ gen_host6(compiler_state_t *cstate, struct in6_addr *addr,
/*NOTREACHED*/
}

static struct block *
gen_host46_byname(compiler_state_t *cstate, const char *name,
const u_char proto4, const u_char proto6, const u_char dir)
{
if (! (cstate->ai = pcap_nametoaddrinfo(name)))
bpf_error(cstate, ERRSTR_UNKNOWN_HOST, name);
struct block *ret = NULL;
struct in6_addr mask128;
memset(&mask128, 0xff, sizeof(mask128));
for (struct addrinfo *ai = cstate->ai; ai; ai = ai->ai_next) {
struct block *tmp = NULL;
switch (ai->ai_family) {
case AF_INET:
switch (proto4) {
case Q_IP:
case Q_ARP:
case Q_RARP:
case Q_DEFAULT:
struct sockaddr_in *sin4 =
(struct sockaddr_in *)ai->ai_addr;
tmp = gen_host(cstate, ntohl(sin4->sin_addr.s_addr),
0xffffffff, proto4, dir, Q_HOST);
}
break;
case AF_INET6:
switch (proto6) {
case Q_IPV6:
case Q_DEFAULT:
struct sockaddr_in6 *sin6 =
(struct sockaddr_in6 *)ai->ai_addr;
tmp = gen_host6(cstate, &sin6->sin6_addr,
&mask128, proto6, dir, Q_HOST);
}
break;
}
if (! tmp)
continue;
if (ret)
gen_or(ret, tmp);
ret = tmp;
}
free(cstate->ai);
cstate->ai = NULL;

if (! ret)
bpf_error(cstate, ERRSTR_UNKNOWN_HOST, name);
return ret;
}

static unsigned char
is_mac48_linktype(const int linktype)
{
Expand Down Expand Up @@ -5312,68 +5363,23 @@ gen_mac48host_byname(compiler_state_t *cstate, const char *name,
* to qualify it with a direction.
*/
static struct block *
gen_gateway(compiler_state_t *cstate, const char *name,
struct addrinfo *alist, int proto)
gen_gateway(compiler_state_t *cstate, const char *name, const int proto)
{
struct block *b0, *b1, *tmp;
struct addrinfo *ai;
struct sockaddr_in *sin;

switch (proto) {
case Q_DEFAULT:
case Q_IP:
case Q_ARP:
case Q_RARP:
b0 = gen_mac48host_byname(cstate, name, Q_OR, "gateway");
b1 = NULL;
for (ai = alist; ai != NULL; ai = ai->ai_next) {
/*
* Does it have an address?
*/
if (ai->ai_addr != NULL) {
/*
* Yes. Is it an IPv4 address?
*/
if (ai->ai_addr->sa_family == AF_INET) {
/*
* Generate an entry for it.
*/
sin = (struct sockaddr_in *)ai->ai_addr;
tmp = gen_host(cstate,
ntohl(sin->sin_addr.s_addr),
0xffffffff, proto, Q_OR, Q_HOST);
/*
* Is it the *first* IPv4 address?
*/
if (b1 == NULL) {
/*
* Yes, so start with it.
*/
b1 = tmp;
} else {
/*
* No, so OR it into the
* existing set of
* addresses.
*/
gen_or(b1, tmp);
b1 = tmp;
}
}
}
}
if (b1 == NULL) {
/*
* No IPv4 addresses found.
*/
return (NULL);
}
gen_not(b1);
gen_and(b0, b1);
return b1;
break;
default:
bpf_error(cstate, ERRSTR_INVALID_QUAL, pqkw(proto), "gateway");
}
bpf_error(cstate, ERRSTR_INVALID_QUAL, pqkw(proto), "gateway");
/*NOTREACHED*/

struct block *b0 = gen_mac48host_byname(cstate, name, Q_OR, "gateway");
struct block *b1 = gen_host46_byname(cstate, name, proto, proto, Q_OR);
gen_not(b1);
gen_and(b0, b1);
return b1;
}

static struct block *
Expand Down Expand Up @@ -6709,14 +6715,8 @@ gen_scode(compiler_state_t *cstate, const char *name, struct qual q)
{
int proto = q.proto;
int dir = q.dir;
int tproto;
bpf_u_int32 mask, addr;
struct addrinfo *res, *res0;
struct sockaddr_in *sin4;
int tproto6;
struct sockaddr_in6 *sin6;
struct in6_addr mask128;
struct block *b, *tmp;
struct block *b;
int port, real_proto;
bpf_u_int32 port1, port2;

Expand Down Expand Up @@ -6753,55 +6753,21 @@ gen_scode(compiler_state_t *cstate, const char *name, struct qual q)
*/
bpf_error(cstate, "invalid DECnet address '%s'", name);
} else {
memset(&mask128, 0xff, sizeof(mask128));
res0 = res = pcap_nametoaddrinfo(name);
if (res == NULL)
bpf_error(cstate, "unknown host '%s'", name);
cstate->ai = res;
b = tmp = NULL;
tproto = proto;
tproto6 = proto;
u_char tproto = q.proto;
u_char tproto6 = q.proto;
if (cstate->off_linktype.constant_part == OFFSET_NOT_SET &&
tproto == Q_DEFAULT) {
/*
* For certain DLTs have "host NAME" mean
* "ip host NAME or ip6 host NAME", but not
* "arp host NAME or rarp host NAME" (here may
* be not the best place for this though).
*/
tproto = Q_IP;
tproto6 = Q_IPV6;
}
for (res = res0; res; res = res->ai_next) {
switch (res->ai_family) {
case AF_INET:
if (tproto == Q_IPV6)
continue;

sin4 = (struct sockaddr_in *)
res->ai_addr;
tmp = gen_host(cstate, ntohl(sin4->sin_addr.s_addr),
0xffffffff, tproto, dir, q.addr);
break;
case AF_INET6:
if (tproto6 == Q_IP)
continue;

sin6 = (struct sockaddr_in6 *)
res->ai_addr;
tmp = gen_host6(cstate, &sin6->sin6_addr,
&mask128, tproto6, dir, q.addr);
break;
default:
continue;
}
if (b)
gen_or(b, tmp);
b = tmp;
}
cstate->ai = NULL;
freeaddrinfo(res0);
if (b == NULL) {
bpf_error(cstate, "unknown host '%s'%s", name,
(proto == Q_DEFAULT)
? ""
: " for specified address family");
}
return b;
return gen_host46_byname(cstate, name, tproto,
tproto6, q.dir);
}

case Q_PORT:
Expand Down Expand Up @@ -6889,16 +6855,7 @@ gen_scode(compiler_state_t *cstate, const char *name, struct qual q)
return b;

case Q_GATEWAY:
res = pcap_nametoaddrinfo(name);
cstate->ai = res;
if (res == NULL)
bpf_error(cstate, "unknown host '%s'", name);
b = gen_gateway(cstate, name, res, proto);
cstate->ai = NULL;
freeaddrinfo(res);
if (b == NULL)
bpf_error(cstate, "unknown host '%s'", name);
return b;
return gen_gateway(cstate, name, proto);

case Q_PROTO:
real_proto = lookup_proto(cstate, name, proto);
Expand Down Expand Up @@ -7112,10 +7069,8 @@ struct block *
gen_mcode6(compiler_state_t *cstate, const char *s, bpf_u_int32 masklen,
struct qual q)
{
struct addrinfo *res;
struct in6_addr *addr;
struct in6_addr addr;
struct in6_addr mask;
struct block *b;
bpf_u_int32 a[4], m[4]; /* Same as in gen_hostop6(). */

/*
Expand All @@ -7125,13 +7080,12 @@ gen_mcode6(compiler_state_t *cstate, const char *s, bpf_u_int32 masklen,
if (setjmp(cstate->top_ctx))
return (NULL);

res = pcap_nametoaddrinfo(s);
if (!res)
bpf_error(cstate, "invalid ip6 address %s", s);
cstate->ai = res;
if (res->ai_next)
bpf_error(cstate, "%s resolved to multiple address", s);
addr = &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr;
/*
* If everything works correctly, this call never fails: a string that
* is valid for HID6 in the lexer is valid for inet_pton().
*/
if (1 != inet_pton(AF_INET6, s, &addr))
bpf_error(cstate, "'%s' is not a valid IPv6 address", s);

if (masklen > sizeof(mask.s6_addr) * 8)
bpf_error(cstate, "mask length must be <= %zu", sizeof(mask.s6_addr) * 8);
Expand All @@ -7142,7 +7096,7 @@ gen_mcode6(compiler_state_t *cstate, const char *s, bpf_u_int32 masklen,
(0xff << (8 - masklen % 8)) & 0xff;
}

memcpy(a, addr, sizeof(a));
memcpy(a, &addr, sizeof(a));
memcpy(m, &mask, sizeof(m));
if ((a[0] & ~m[0]) || (a[1] & ~m[1])
|| (a[2] & ~m[2]) || (a[3] & ~m[3])) {
Expand All @@ -7158,10 +7112,7 @@ gen_mcode6(compiler_state_t *cstate, const char *s, bpf_u_int32 masklen,
/* FALLTHROUGH */

case Q_NET:
b = gen_host6(cstate, addr, &mask, q.proto, q.dir, q.addr);
cstate->ai = NULL;
freeaddrinfo(res);
return b;
return gen_host6(cstate, &addr, &mask, q.proto, q.dir, q.addr);

default:
// Q_GATEWAY only (see the grammar)
Expand Down
2 changes: 2 additions & 0 deletions testprogs/TESTrun
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Original file line number Diff line number Diff line change
Expand Up @@ -8776,6 +8776,8 @@ my @accept_blocks = (
'ip src or dst noeth-ipv4-ipv6.host123.libpcap.test',
'ip src or dst host noeth-ipv4-noipv6.host123.libpcap.test',
'ip src or dst host noeth-ipv4-ipv6.host123.libpcap.test',
# This does not mean "arp host" or "rarp host" because for
# DLT_RAW off_linktype.constant_part == OFFSET_NOT_SET.
'host noeth-ipv4-noipv6.host123.libpcap.test',
'src or dst noeth-ipv4-noipv6.host123.libpcap.test',
'src or dst host noeth-ipv4-noipv6.host123.libpcap.test',
Expand Down