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nfqws2: simplify complex unwinds in lua code

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bol-van
2026-01-15 11:40:39 +03:00
parent 17bdfe16b1
commit f919533873
2 changed files with 31 additions and 40 deletions
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69
nfq2/lua.c
View File

@@ -1630,10 +1630,10 @@ static bool lua_reconstruct_ip6exthdr(lua_State *L, int idx, struct ip6_hdr *ip6
}
else
{
if (lua_type(L,-1)!=LUA_TTABLE) goto err2;
if (lua_type(L,-1)!=LUA_TTABLE) goto err;
lua_getfield(L,-1, "type");
if (lua_type(L,-1)!=LUA_TNUMBER) goto err3;
if (lua_type(L,-1)!=LUA_TNUMBER) goto err;
type = (uint8_t)lua_tointeger(L,-1);
lua_pop(L, 1);
@@ -1642,9 +1642,9 @@ static bool lua_reconstruct_ip6exthdr(lua_State *L, int idx, struct ip6_hdr *ip6
lua_pop(L, 1);
lua_getfield(L,-1, "data");
if (lua_type(L,-1)!=LUA_TSTRING) goto err3;
if (lua_type(L,-1)!=LUA_TSTRING) goto err;
if (!(p=(uint8_t*)lua_tolstring(L,-1,&l))) l=0;
if (!l || (l+2)>left || ((type==IPPROTO_AH) ? (l<6 || ((l+2) & 3)) : ((l+2) & 7))) goto err3;
if (!l || (l+2)>left || ((type==IPPROTO_AH) ? (l<6 || ((l+2) & 3)) : ((l+2) & 7))) goto err;
memcpy(data+2,p,l);
l+=2;
data[0] = next; // may be overwritten later
@@ -1663,13 +1663,8 @@ static bool lua_reconstruct_ip6exthdr(lua_State *L, int idx, struct ip6_hdr *ip6
lua_pop(L, 1);
LUA_STACK_GUARD_LEAVE(L, 0)
return true;
err2:
lua_pop(L, 2);
goto err;
err3:
lua_pop(L, 3);
err:
LUA_STACK_GUARD_LEAVE(L, 0)
LUA_STACK_GUARD_UNWIND_RETURN(L, 0)
return false;
}
bool lua_reconstruct_ip6hdr(lua_State *L, int idx, struct ip6_hdr *ip6, size_t *len, uint8_t last_proto, bool preserve_next)
@@ -1712,7 +1707,10 @@ bool lua_reconstruct_ip6hdr(lua_State *L, int idx, struct ip6_hdr *ip6, size_t *
if (!p || l!=sizeof(struct in6_addr)) goto err;
ip6->ip6_dst = *(struct in6_addr*)p;
lua_pop(L, 1);
return lua_reconstruct_ip6exthdr(L, idx, ip6, len, last_proto, preserve_next);
bool b = lua_reconstruct_ip6exthdr(L, idx, ip6, len, last_proto, preserve_next);
LUA_STACK_GUARD_LEAVE(L, 0)
return b;
err:
lua_pop(L, 1);
@@ -1863,10 +1861,10 @@ static bool lua_reconstruct_tcphdr_options(lua_State *L, int idx, struct tcphdr
{
// uses 'key' (at index -2) and 'value' (at index -1)
if (!left || lua_type(L,-1)!=LUA_TTABLE) goto err2;
if (!left || lua_type(L,-1)!=LUA_TTABLE) goto err;
lua_getfield(L,-1, "kind");
if (lua_type(L,-1)!=LUA_TNUMBER) goto err3;
if (lua_type(L,-1)!=LUA_TNUMBER) goto err;
kind = (uint8_t)lua_tointeger(L,-1);
lua_pop(L, 1);
@@ -1884,7 +1882,7 @@ static bool lua_reconstruct_tcphdr_options(lua_State *L, int idx, struct tcphdr
lua_getfield(L,-1, "data");
l = 0;
p = lua_type(L,-1)==LUA_TSTRING ? (uint8_t*)lua_tolstring(L,-1,&l) : NULL;
if ((2+l)>left) goto err3;
if ((2+l)>left) goto err;
if (p) memcpy(data+2,p,l);
l+=2;
data[0] = kind;
@@ -1900,7 +1898,7 @@ static bool lua_reconstruct_tcphdr_options(lua_State *L, int idx, struct tcphdr
end:
while(filled & 3)
{
if (!left) goto err1;
if (!left) goto err;
*data = TCP_KIND_NOOP; data++; left--; filled++;
}
}
@@ -1911,16 +1909,8 @@ end:
lua_pop(L, 1);
LUA_STACK_GUARD_LEAVE(L, 0)
return true;
err1:
lua_pop(L, 1);
goto err;
err2:
lua_pop(L, 2);
goto err;
err3:
lua_pop(L, 3);
err:
LUA_STACK_GUARD_LEAVE(L, 0)
LUA_STACK_GUARD_UNWIND_RETURN(L, 0)
return false;
}
bool lua_reconstruct_tcphdr(lua_State *L, int idx, struct tcphdr *tcp, size_t *len)
@@ -1975,8 +1965,9 @@ bool lua_reconstruct_tcphdr(lua_State *L, int idx, struct tcphdr *tcp, size_t *l
tcp->th_off = 5;
bool b = lua_reconstruct_tcphdr_options(L, idx, tcp, len);
LUA_STACK_GUARD_LEAVE(L, 0)
return lua_reconstruct_tcphdr_options(L, idx, tcp, len);
return b;
err:
lua_pop(L, 1);
LUA_STACK_GUARD_LEAVE(L, 0)
@@ -2078,7 +2069,7 @@ bool lua_reconstruct_dissect(lua_State *L, int idx, uint8_t *buf, size_t *len, b
if (!lua_reconstruct_iphdr(L,-1, ip, &l))
{
DLOG_ERR("reconstruct_dissect: bad ip\n");
goto err1;
goto err;
}
ip4_fix_checksum(ip);
}
@@ -2086,12 +2077,12 @@ bool lua_reconstruct_dissect(lua_State *L, int idx, uint8_t *buf, size_t *len, b
{
lua_pop(L, 1);
lua_getfield(L,idx,"ip6");
if (lua_type(L,-1)!=LUA_TTABLE) goto err1;
if (lua_type(L,-1)!=LUA_TTABLE) goto err;
ip6 = (struct ip6_hdr*)data;
if (!lua_reconstruct_ip6hdr(L,-1, ip6, &l, lua_ip6_l4proto_from_dissect(L,idx), ip6_preserve_next))
{
DLOG_ERR("reconstruct_dissect: bad ip6\n");
goto err1;
goto err;
}
}
l3=l;
@@ -2106,7 +2097,7 @@ bool lua_reconstruct_dissect(lua_State *L, int idx, uint8_t *buf, size_t *len, b
if (!lua_reconstruct_tcphdr(L, -1, tcp, &l))
{
DLOG_ERR("reconstruct_dissect: bad tcp\n");
goto err1;
goto err;
}
}
else
@@ -2114,12 +2105,12 @@ bool lua_reconstruct_dissect(lua_State *L, int idx, uint8_t *buf, size_t *len, b
lua_pop(L, 1);
lua_getfield(L,idx,"udp");
l = sizeof(struct udphdr);
if (lua_type(L,-1)!=LUA_TTABLE || left<l) goto err1;
if (lua_type(L,-1)!=LUA_TTABLE || left<l) goto err;
udp = (struct udphdr*)data;
if (!lua_reconstruct_udphdr(L, -1, udp))
{
DLOG_ERR("reconstruct_dissect: bad udp\n");
goto err1;
goto err;
}
}
data+=l; left-=l;
@@ -2129,7 +2120,7 @@ bool lua_reconstruct_dissect(lua_State *L, int idx, uint8_t *buf, size_t *len, b
p = lua_tolstring(L,-1,&lpayload);
if (p)
{
if (left<lpayload) goto err0;
if (left<lpayload) goto err;
memcpy(data,p,lpayload);
data+=lpayload; left-=lpayload;
}
@@ -2161,12 +2152,12 @@ bool lua_reconstruct_dissect(lua_State *L, int idx, uint8_t *buf, size_t *len, b
if (iplen<l3 || iplen>l)
{
DLOG_ERR("ipv4 frag : invalid ip_len\n");
goto err0;
goto err;
}
if (frag_start>l)
{
DLOG_ERR("ipv4 frag : fragment offset is outside of the packet\n");
goto err0;
goto err;
}
if (off) memmove(buf+l3,buf+l3+off,iplen-l3);
l = iplen; // shrink packet to iplen
@@ -2189,13 +2180,13 @@ bool lua_reconstruct_dissect(lua_State *L, int idx, uint8_t *buf, size_t *len, b
if (size_unfragmentable > plen)
{
DLOG_ERR("ipv6 frag : invalid ip6_plen\n");
goto err0;
goto err;
}
size_t size_fragmentable = plen - size_unfragmentable;
if ((endfrag + off + size_fragmentable) > data)
{
DLOG_ERR("ipv6 frag : fragmentable part is outside of the packet\n");
goto err0;
goto err;
}
if (off) memmove(endfrag, endfrag + off, size_fragmentable);
l = sizeof(struct ip6_hdr) + plen;
@@ -2207,10 +2198,8 @@ bool lua_reconstruct_dissect(lua_State *L, int idx, uint8_t *buf, size_t *len, b
*len = l;
LUA_STACK_GUARD_LEAVE(L, 0)
return true;
err1:
lua_pop(L, 1);
err0:
LUA_STACK_GUARD_LEAVE(L, 0)
err:
LUA_STACK_GUARD_UNWIND_RETURN(L, 0)
return false;
}
static int luacall_reconstruct_dissect(lua_State *L)

2
nfq2/lua.h
View File

@@ -38,6 +38,8 @@
#define LUA_STACK_GUARD_ENTER(L) int _lsg=lua_gettop(L);
#define LUA_STACK_GUARD_LEAVE(L,N) if ((_lsg+N)!=lua_gettop(L)) luaL_error(L,"stack guard failure");
#define LUA_STACK_GUARD_RETURN(L,N) LUA_STACK_GUARD_LEAVE(L,N); return N;
#define LUA_STACK_GUARD_UNWIND(L) lua_settop(L,_lsg);
#define LUA_STACK_GUARD_UNWIND_RETURN(L,N) LUA_STACK_GUARD_UNWIND(L); return N;
void desync_instance(const char *func, unsigned int dp_n, unsigned int func_n, char *instance, size_t inst_size);