1387 lines
24 KiB
C
1387 lines
24 KiB
C
/*
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that: (1) source code distributions
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* retain the above copyright notice and this paragraph in its entirety, (2)
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* distributions including binary code include the above copyright notice and
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* this paragraph in its entirety in the documentation or other materials
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* provided with the distribution, and (3) all advertising materials mentioning
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* features or use of this software display the following acknowledgement:
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* ``This product includes software developed by the University of California,
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* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
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* the University nor the names of its contributors may be used to endorse
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* or promote products derived from this software without specific prior
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* written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*
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* $Id: gencode.c,v 1.1 1993/11/14 21:20:09 deraadt Exp $
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*/
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#ifndef lint
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static char rcsid[] =
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"@(#) Header: gencode.c,v 1.33 92/05/22 16:38:39 mccanne Exp (LBL)";
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#endif
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#ifdef __STDC__
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#include <stdlib.h>
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#endif
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <net/if.h>
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#include <netinet/in.h>
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#include <netinet/if_ether.h>
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#include <sys/time.h>
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#include <net/bpf.h>
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#include "interface.h"
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#include "gencode.h"
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#include "nametoaddr.h"
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#include "extract.h"
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#define JMP(c) ((c)|BPF_JMP|BPF_K)
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extern struct bpf_insn *icode_to_fcode();
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extern u_long net_mask();
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static void init_linktype();
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static int alloc_reg();
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static void free_reg();
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static struct block *root;
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/*
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* We divy out chunks of memory rather than call malloc each time so
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* we don't have to worry about leaking memory. It's probably
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* not a big deal if all this memory was wasted but it this ever
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* goes into a library that would probably not be a good idea.
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*/
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#define NCHUNKS 16
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#define CHUNK0SIZE 1024
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struct chunk {
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u_int n_left;
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void *m;
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};
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static struct chunk chunks[NCHUNKS];
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static int cur_chunk;
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static void *
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newchunk(n)
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u_int n;
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{
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struct chunk *cp;
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int k, size;
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/* XXX Round up to nearest long. */
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n = (n + sizeof(long) - 1) & ~(sizeof(long) - 1);
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cp = &chunks[cur_chunk];
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if (n > cp->n_left) {
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++cp, k = ++cur_chunk;
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if (k >= NCHUNKS)
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error("out of memory");
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size = CHUNK0SIZE << k;
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cp->m = (void *)malloc(size);
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bzero((char *)cp->m, size);
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cp->n_left = size;
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if (n > size)
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error("out of memory");
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}
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cp->n_left -= n;
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return (void *)((char *)cp->m + cp->n_left);
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}
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static void
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freechunks()
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{
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int i;
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for (i = 0; i < NCHUNKS; ++i)
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if (chunks[i].m)
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free(chunks[i].m);
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}
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static inline struct block *
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new_block(code)
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int code;
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{
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struct block *p;
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p = (struct block *)newchunk(sizeof(*p));
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p->s.code = code;
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p->head = p;
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return p;
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}
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static inline struct slist *
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new_stmt(code)
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int code;
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{
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struct slist *p;
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p = (struct slist *)newchunk(sizeof(*p));
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p->s.code = code;
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return p;
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}
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static struct block *
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gen_retblk(v)
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int v;
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{
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struct block *b = new_block(BPF_RET|BPF_K);
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b->s.k = v;
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return b;
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}
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static inline void
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syntax()
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{
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error("syntax error in filter expression");
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}
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static u_long netmask;
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struct bpf_program *
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parse(buf, Oflag, linktype, mask)
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char *buf;
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int Oflag;
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int linktype;
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u_long mask;
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{
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extern int n_errors;
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static struct bpf_program F;
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struct bpf_insn *p;
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int len;
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netmask = mask;
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F.bf_insns = 0;
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F.bf_len = 0;
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lex_init(buf ? buf : "");
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init_linktype(linktype);
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yyparse();
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if (n_errors)
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syntax();
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if (root == 0)
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root = gen_retblk(snaplen);
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if (Oflag) {
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optimize(&root);
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if (root == 0 ||
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(root->s.code == (BPF_RET|BPF_K) && root->s.k == 0))
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error("expression rejects all packets");
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}
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p = icode_to_fcode(root, &len);
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F.bf_insns = p;
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F.bf_len = len;
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freechunks();
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return &F;
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}
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/*
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* Backpatch the blocks in 'list' to 'target'. The 'sense' field indicates
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* which of the jt and jf fields has been resolved and which is a pointer
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* back to another unresolved block (or nil). At least one of the fields
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* in each block is already resolved.
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*/
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static void
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backpatch(list, target)
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struct block *list, *target;
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{
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struct block *next;
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while (list) {
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if (!list->sense) {
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next = JT(list);
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JT(list) = target;
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} else {
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next = JF(list);
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JF(list) = target;
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}
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list = next;
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}
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}
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/*
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* Merge the lists in b0 and b1, using the 'sense' field to indicate
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* which of jt and jf is the link.
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*/
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static void
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merge(b0, b1)
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struct block *b0, *b1;
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{
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register struct block **p = &b0;
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/* Find end of list. */
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while (*p)
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p = !((*p)->sense) ? &JT(*p) : &JF(*p);
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/* Concatenate the lists. */
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*p = b1;
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}
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void
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finish_parse(p)
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struct block *p;
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{
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backpatch(p, gen_retblk(snaplen));
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p->sense = !p->sense;
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backpatch(p, gen_retblk(0));
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root = p->head;
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}
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void
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gen_and(b0, b1)
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struct block *b0, *b1;
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{
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backpatch(b0, b1->head);
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b0->sense = !b0->sense;
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b1->sense = !b1->sense;
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merge(b1, b0);
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b1->sense = !b1->sense;
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b1->head = b0->head;
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}
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void
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gen_or(b0, b1)
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struct block *b0, *b1;
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{
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b0->sense = !b0->sense;
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backpatch(b0, b1->head);
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b0->sense = !b0->sense;
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merge(b1, b0);
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b1->head = b0->head;
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}
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void
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gen_not(b)
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struct block *b;
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{
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b->sense = !b->sense;
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}
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static struct block *
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gen_cmp(offset, size, v)
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u_int offset, size;
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long v;
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{
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struct slist *s;
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struct block *b;
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s = new_stmt(BPF_LD|BPF_ABS|size);
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s->s.k = offset;
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b = new_block(JMP(BPF_JEQ));
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b->stmts = s;
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b->s.k = v;
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return b;
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}
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struct block *
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gen_mcmp(offset, size, v, mask)
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u_int offset, size;
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long v;
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u_long mask;
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{
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struct block *b = gen_cmp(offset, size, v);
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struct slist *s;
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if (mask != 0xffffffff) {
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s = new_stmt(BPF_ALU|BPF_AND|BPF_K);
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s->s.k = mask;
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b->stmts->next = s;
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}
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return b;
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}
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struct block *
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gen_bcmp(offset, size, v)
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u_int offset;
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u_int size;
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u_char *v;
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{
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struct block *b, *tmp;
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int k;
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b = 0;
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while (size >= 4) {
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k = size - 4;
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tmp = gen_cmp(offset + k, BPF_W, EXTRACT_LONG(&v[k]));
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if (b != 0)
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gen_and(b, tmp);
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b = tmp;
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size -= 4;
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}
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while (size >= 2) {
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k = size - 2;
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tmp = gen_cmp(offset + k, BPF_H, (long)EXTRACT_SHORT(&v[k]));
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if (b != 0)
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gen_and(b, tmp);
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b = tmp;
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size -= 2;
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}
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if (size > 0) {
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tmp = gen_cmp(offset, BPF_B, (long)v[0]);
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if (b != 0)
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gen_and(b, tmp);
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b = tmp;
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}
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return b;
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}
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/*
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* Various code contructs need to know the layout of the data link
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* layer. These variables give the necessary offsets. off_linktype
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* is set to -1 for no encapsulation, in which case, IP is assumed.
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*/
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static u_int off_linktype;
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static u_int off_nl;
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static int linktype;
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static void
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init_linktype(type)
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int type;
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{
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linktype = type;
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switch (type) {
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case DLT_EN10MB:
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off_linktype = 12;
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off_nl = 14;
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return;
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case DLT_SLIP:
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/*
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* SLIP doesn't have a link level type. The 16 byte
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* header is hacked into our SLIP driver.
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*/
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off_linktype = -1;
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off_nl = 16;
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return;
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case DLT_NULL:
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off_linktype = -1;
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off_nl = 0;
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return;
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case DLT_PPP:
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off_linktype = 2;
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off_nl = 4;
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return;
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case DLT_FDDI:
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off_linktype = 19;
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off_nl = 21;
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return;
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case DLT_IEEE802:
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off_linktype = 20;
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off_nl = 22;
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return;
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}
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error("unknown data link type 0x%x", linktype);
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/* NOTREACHED */
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}
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static struct block *
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gen_uncond(rsense)
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int rsense;
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{
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struct block *b;
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struct slist *s;
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s = new_stmt(BPF_LD|BPF_IMM);
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s->s.k = !rsense;
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b = new_block(JMP(BPF_JEQ));
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b->stmts = s;
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return b;
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}
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static inline struct block *
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gen_true()
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{
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return gen_uncond(1);
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}
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static inline struct block *
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gen_false()
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{
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return gen_uncond(0);
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}
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struct block *
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gen_linktype(proto)
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int proto;
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{
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switch (linktype) {
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case DLT_SLIP:
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if (proto == ETHERTYPE_IP)
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return gen_true();
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else
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return gen_false();
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case DLT_PPP:
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if (proto == ETHERTYPE_IP)
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proto = 0x0021; /* XXX - need ppp.h defs */
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break;
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}
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return gen_cmp(off_linktype, BPF_H, (long)proto);
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}
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static struct block *
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gen_hostop(addr, mask, dir, proto, src_off, dst_off)
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u_long addr;
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u_long mask;
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int dir, proto;
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u_int src_off, dst_off;
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{
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struct block *b0, *b1;
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u_int offset;
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switch (dir) {
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case Q_SRC:
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offset = src_off;
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break;
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case Q_DST:
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offset = dst_off;
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break;
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case Q_AND:
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b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off);
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b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off);
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gen_and(b0, b1);
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return b1;
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case Q_OR:
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case Q_DEFAULT:
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b0 = gen_hostop(addr, mask, Q_SRC, proto, src_off, dst_off);
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b1 = gen_hostop(addr, mask, Q_DST, proto, src_off, dst_off);
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gen_or(b0, b1);
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return b1;
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default:
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abort();
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}
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b0 = gen_linktype(proto);
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b1 = gen_mcmp(offset, BPF_W, (long)addr, mask);
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gen_and(b0, b1);
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return b1;
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}
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static struct block *
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gen_ehostop(eaddr, dir)
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u_char *eaddr;
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int dir;
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{
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struct block *b0, *b1;
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switch (dir) {
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case Q_SRC:
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return gen_bcmp(6, 6, eaddr);
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case Q_DST:
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return gen_bcmp(0, 6, eaddr);
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case Q_AND:
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b0 = gen_ehostop(eaddr, Q_SRC);
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b1 = gen_ehostop(eaddr, Q_DST);
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gen_and(b0, b1);
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return b1;
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case Q_DEFAULT:
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case Q_OR:
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b0 = gen_ehostop(eaddr, Q_SRC);
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b1 = gen_ehostop(eaddr, Q_DST);
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gen_or(b0, b1);
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return b1;
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}
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|
abort();
|
|
/* NOTREACHED */
|
|
}
|
|
|
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static struct block *
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gen_host(addr, mask, proto, dir)
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u_long addr;
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u_long mask;
|
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int proto;
|
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int dir;
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{
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struct block *b0, *b1;
|
|
|
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switch (proto) {
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case Q_DEFAULT:
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b0 = gen_host(addr, mask, Q_IP, dir);
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b1 = gen_host(addr, mask, Q_ARP, dir);
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gen_or(b0, b1);
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b0 = gen_host(addr, mask, Q_RARP, dir);
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gen_or(b1, b0);
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return b0;
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|
|
|
case Q_IP:
|
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return gen_hostop(addr, mask, dir, ETHERTYPE_IP,
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off_nl + 12, off_nl + 16);
|
|
|
|
case Q_RARP:
|
|
return gen_hostop(addr, mask, dir, ETHERTYPE_REVARP,
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|
off_nl + 14, off_nl + 24);
|
|
|
|
case Q_ARP:
|
|
return gen_hostop(addr, mask, dir, ETHERTYPE_ARP,
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|
off_nl + 14, off_nl + 24);
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|
|
|
case Q_TCP:
|
|
error("'tcp' modifier applied to host");
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|
|
|
case Q_UDP:
|
|
error("'udp' modifier applied to host");
|
|
|
|
case Q_ICMP:
|
|
error("'icmp' modifier applied to host");
|
|
}
|
|
abort();
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
static struct block *
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|
gen_gateway(eaddr, alist, proto, dir)
|
|
u_char *eaddr;
|
|
u_long **alist;
|
|
int proto;
|
|
int dir;
|
|
{
|
|
struct block *b0, *b1, *tmp;
|
|
|
|
if (dir != 0)
|
|
error("direction applied to 'gateway'");
|
|
|
|
switch (proto) {
|
|
case Q_DEFAULT:
|
|
case Q_IP:
|
|
case Q_ARP:
|
|
case Q_RARP:
|
|
b0 = gen_ehostop(eaddr, Q_OR);
|
|
b1 = gen_host(**alist++, 0xffffffffL, proto, Q_OR);
|
|
while (*alist) {
|
|
tmp = gen_host(**alist++, 0xffffffffL, proto, Q_OR);
|
|
gen_or(b1, tmp);
|
|
b1 = tmp;
|
|
}
|
|
gen_not(b1);
|
|
gen_and(b0, b1);
|
|
return b1;
|
|
}
|
|
error("illegal modifier of 'gateway'");
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
struct block *
|
|
gen_proto_abbrev(proto)
|
|
int proto;
|
|
{
|
|
struct block *b0, *b1;
|
|
|
|
switch (proto) {
|
|
|
|
case Q_TCP:
|
|
b0 = gen_linktype(ETHERTYPE_IP);
|
|
b1 = gen_cmp(off_nl + 9, BPF_B, (long)IPPROTO_TCP);
|
|
gen_and(b0, b1);
|
|
break;
|
|
|
|
case Q_UDP:
|
|
b0 = gen_linktype(ETHERTYPE_IP);
|
|
b1 = gen_cmp(off_nl + 9, BPF_B, (long)IPPROTO_UDP);
|
|
gen_and(b0, b1);
|
|
break;
|
|
|
|
case Q_ICMP:
|
|
b0 = gen_linktype(ETHERTYPE_IP);
|
|
b1 = gen_cmp(off_nl + 9, BPF_B, (long)IPPROTO_ICMP);
|
|
gen_and(b0, b1);
|
|
break;
|
|
|
|
case Q_IP:
|
|
b1 = gen_linktype(ETHERTYPE_IP);
|
|
break;
|
|
|
|
case Q_ARP:
|
|
b1 = gen_linktype(ETHERTYPE_ARP);
|
|
break;
|
|
|
|
case Q_RARP:
|
|
b1 = gen_linktype(ETHERTYPE_REVARP);
|
|
break;
|
|
|
|
case Q_LINK:
|
|
error("link layer applied in wrong context");
|
|
|
|
default:
|
|
abort();
|
|
}
|
|
return b1;
|
|
}
|
|
|
|
static struct block *
|
|
gen_ipfrag()
|
|
{
|
|
struct slist *s;
|
|
struct block *b;
|
|
|
|
/* not ip frag */
|
|
s = new_stmt(BPF_LD|BPF_H|BPF_ABS);
|
|
s->s.k = off_nl + 6;
|
|
b = new_block(JMP(BPF_JSET));
|
|
b->s.k = 0x1fff;
|
|
b->stmts = s;
|
|
gen_not(b);
|
|
|
|
return b;
|
|
}
|
|
|
|
static struct block *
|
|
gen_portatom(off, v)
|
|
int off;
|
|
long v;
|
|
{
|
|
struct slist *s;
|
|
struct block *b;
|
|
|
|
s = new_stmt(BPF_LDX|BPF_MSH|BPF_B);
|
|
s->s.k = off_nl;
|
|
|
|
s->next = new_stmt(BPF_LD|BPF_IND|BPF_H);
|
|
s->next->s.k = off_nl + off;
|
|
|
|
b = new_block(JMP(BPF_JEQ));
|
|
b->stmts = s;
|
|
b->s.k = v;
|
|
|
|
return b;
|
|
}
|
|
|
|
struct block *
|
|
gen_portop(port, proto, dir)
|
|
int port;
|
|
int proto;
|
|
int dir;
|
|
{
|
|
struct block *b0, *b1, *tmp;
|
|
|
|
/* ip proto 'proto' */
|
|
tmp = gen_cmp(off_nl + 9, BPF_B, (long)proto);
|
|
b0 = gen_ipfrag();
|
|
gen_and(tmp, b0);
|
|
|
|
switch (dir) {
|
|
case Q_SRC:
|
|
b1 = gen_portatom(0, (long)port);
|
|
break;
|
|
|
|
case Q_DST:
|
|
b1 = gen_portatom(2, (long)port);
|
|
break;
|
|
|
|
case Q_OR:
|
|
case Q_DEFAULT:
|
|
tmp = gen_portatom(0, (long)port);
|
|
b1 = gen_portatom(2, (long)port);
|
|
gen_or(tmp, b1);
|
|
break;
|
|
|
|
case Q_AND:
|
|
tmp = gen_portatom(0, (long)port);
|
|
b1 = gen_portatom(2, (long)port);
|
|
gen_and(tmp, b1);
|
|
break;
|
|
|
|
default:
|
|
abort();
|
|
}
|
|
gen_and(b0, b1);
|
|
|
|
return b1;
|
|
}
|
|
|
|
static struct block *
|
|
gen_port(port, ip_proto, dir)
|
|
int port;
|
|
int ip_proto;
|
|
int dir;
|
|
{
|
|
struct block *b0, *b1, *tmp;
|
|
|
|
/* ether proto ip */
|
|
b0 = gen_linktype(ETHERTYPE_IP);
|
|
|
|
switch (ip_proto) {
|
|
case IPPROTO_UDP:
|
|
case IPPROTO_TCP:
|
|
b1 = gen_portop(port, ip_proto, dir);
|
|
break;
|
|
|
|
case PROTO_UNDEF:
|
|
tmp = gen_portop(port, IPPROTO_TCP, dir);
|
|
b1 = gen_portop(port, IPPROTO_UDP, dir);
|
|
gen_or(tmp, b1);
|
|
break;
|
|
|
|
default:
|
|
abort();
|
|
}
|
|
gen_and(b0, b1);
|
|
return b1;
|
|
}
|
|
|
|
int
|
|
lookup_proto(name, proto)
|
|
char *name;
|
|
int proto;
|
|
{
|
|
int v;
|
|
|
|
switch (proto) {
|
|
case Q_DEFAULT:
|
|
case Q_IP:
|
|
v = s_nametoproto(name);
|
|
if (v == PROTO_UNDEF)
|
|
error("unknown ip proto '%s'", name);
|
|
break;
|
|
|
|
case Q_LINK:
|
|
/* XXX should look up h/w protocol type based on linktype */
|
|
v = s_nametoeproto(name);
|
|
if (v == PROTO_UNDEF)
|
|
error("unknown ether proto '%s'", name);
|
|
break;
|
|
|
|
default:
|
|
v = PROTO_UNDEF;
|
|
break;
|
|
}
|
|
return v;
|
|
}
|
|
|
|
struct block *
|
|
gen_proto(v, proto, dir)
|
|
int v;
|
|
int proto;
|
|
int dir;
|
|
{
|
|
struct block *b0, *b1;
|
|
|
|
if (dir != Q_DEFAULT)
|
|
error("direction applied to 'proto'");
|
|
|
|
switch (proto) {
|
|
case Q_DEFAULT:
|
|
case Q_IP:
|
|
b0 = gen_linktype(ETHERTYPE_IP);
|
|
b1 = gen_cmp(off_nl + 9, BPF_B, (long)v);
|
|
gen_and(b0, b1);
|
|
return b1;
|
|
|
|
case Q_ARP:
|
|
error("arp does not encapsulate another protocol");
|
|
/* NOTREACHED */
|
|
|
|
case Q_RARP:
|
|
error("rarp does not encapsulate another protocol");
|
|
/* NOTREACHED */
|
|
|
|
case Q_LINK:
|
|
return gen_linktype(v);
|
|
|
|
case Q_UDP:
|
|
error("'udp proto' is bogus");
|
|
|
|
case Q_TCP:
|
|
error("'tcp proto' is bogus");
|
|
|
|
case Q_ICMP:
|
|
error("'icmp proto' is bogus");
|
|
}
|
|
abort();
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
struct block *
|
|
gen_scode(name, q)
|
|
char *name;
|
|
struct qual q;
|
|
{
|
|
int proto = q.proto;
|
|
int dir = q.dir;
|
|
u_char *eaddr;
|
|
u_long mask, addr, **alist;
|
|
struct block *b, *tmp;
|
|
int port, real_proto;
|
|
|
|
switch (q.addr) {
|
|
|
|
case Q_NET:
|
|
addr = s_nametonetaddr(name);
|
|
if (addr == 0)
|
|
error("unknown network '%s'", name);
|
|
mask = net_mask(&addr);
|
|
return gen_host(addr, mask, proto, dir);
|
|
|
|
case Q_DEFAULT:
|
|
case Q_HOST:
|
|
if (proto == Q_LINK) {
|
|
/* XXX Should lookup hw addr based on link layer */
|
|
eaddr = ETHER_hostton(name);
|
|
if (eaddr == 0)
|
|
error("unknown ether host '%s'", name);
|
|
return gen_ehostop(eaddr, dir);
|
|
|
|
} else {
|
|
alist = s_nametoaddr(name);
|
|
if (alist == 0 || *alist == 0)
|
|
error("uknown host '%s'", name);
|
|
b = gen_host(**alist++, 0xffffffffL, proto, dir);
|
|
while (*alist) {
|
|
tmp = gen_host(**alist++, 0xffffffffL,
|
|
proto, dir);
|
|
gen_or(b, tmp);
|
|
b = tmp;
|
|
}
|
|
return b;
|
|
}
|
|
|
|
case Q_PORT:
|
|
if (proto != Q_DEFAULT && proto != Q_UDP && proto != Q_TCP)
|
|
error("illegal qualifier of 'port'");
|
|
if (s_nametoport(name, &port, &real_proto) == 0)
|
|
error("unknown port '%s'", name);
|
|
if (proto == Q_UDP) {
|
|
if (real_proto == IPPROTO_TCP)
|
|
error("port '%s' is tcp", name);
|
|
else
|
|
/* override PROTO_UNDEF */
|
|
real_proto = IPPROTO_UDP;
|
|
}
|
|
if (proto == Q_TCP) {
|
|
if (real_proto == IPPROTO_UDP)
|
|
error("port '%s' is udp", name);
|
|
else
|
|
/* override PROTO_UNDEF */
|
|
real_proto = IPPROTO_TCP;
|
|
}
|
|
return gen_port(port, real_proto, dir);
|
|
|
|
case Q_GATEWAY:
|
|
eaddr = ETHER_hostton(name);
|
|
if (eaddr == 0)
|
|
error("unknown ether host: %s", name);
|
|
|
|
alist = s_nametoaddr(name);
|
|
if (alist == 0 || *alist == 0)
|
|
error("uknown host '%s'", name);
|
|
return gen_gateway(eaddr, alist, proto, dir);
|
|
|
|
case Q_PROTO:
|
|
real_proto = lookup_proto(name, proto);
|
|
if (real_proto >= 0)
|
|
return gen_proto(real_proto, proto, dir);
|
|
else
|
|
error("unknown protocol: %s", name);
|
|
|
|
case Q_UNDEF:
|
|
syntax();
|
|
/* NOTREACHED */
|
|
}
|
|
abort();
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
struct block *
|
|
gen_ncode(v, q)
|
|
u_long v;
|
|
struct qual q;
|
|
{
|
|
u_long mask;
|
|
int proto = q.proto;
|
|
int dir = q.dir;
|
|
|
|
switch (q.addr) {
|
|
|
|
case Q_DEFAULT:
|
|
case Q_HOST:
|
|
case Q_NET:
|
|
mask = net_mask(&v);
|
|
return gen_host(v, mask, proto, dir);
|
|
|
|
case Q_PORT:
|
|
if (proto == Q_UDP)
|
|
proto = IPPROTO_UDP;
|
|
else if (proto == Q_TCP)
|
|
proto = IPPROTO_TCP;
|
|
else if (proto == Q_DEFAULT)
|
|
proto = PROTO_UNDEF;
|
|
else
|
|
error("illegal qualifier of 'port'");
|
|
|
|
return gen_port((int)v, proto, dir);
|
|
|
|
case Q_GATEWAY:
|
|
error("'gateway' requires a name");
|
|
/* NOTREACHED */
|
|
|
|
case Q_PROTO:
|
|
return gen_proto((int)v, proto, dir);
|
|
|
|
case Q_UNDEF:
|
|
syntax();
|
|
/* NOTREACHED */
|
|
}
|
|
abort();
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
struct block *
|
|
gen_ecode(eaddr, q)
|
|
u_char *eaddr;
|
|
struct qual q;
|
|
{
|
|
if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK)
|
|
return gen_ehostop(eaddr, (int)q.dir);
|
|
else
|
|
error("ethernet address used in non-ether expression");
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
void
|
|
sappend(s0, s1)
|
|
struct slist *s0, *s1;
|
|
{
|
|
/*
|
|
* This is definitely not the best way to do this, but the
|
|
* lists will rarely get long.
|
|
*/
|
|
while (s0->next)
|
|
s0 = s0->next;
|
|
s0->next = s1;
|
|
}
|
|
|
|
struct slist *
|
|
xfer_to_x(a)
|
|
struct arth *a;
|
|
{
|
|
struct slist *s;
|
|
|
|
s = new_stmt(BPF_LDX|BPF_MEM);
|
|
s->s.k = a->regno;
|
|
return s;
|
|
}
|
|
|
|
struct slist *
|
|
xfer_to_a(a)
|
|
struct arth *a;
|
|
{
|
|
struct slist *s;
|
|
|
|
s = new_stmt(BPF_LD|BPF_MEM);
|
|
s->s.k = a->regno;
|
|
return s;
|
|
}
|
|
|
|
struct arth *
|
|
gen_load(proto, index, size)
|
|
int proto;
|
|
struct arth *index;
|
|
int size;
|
|
{
|
|
struct slist *s, *tmp;
|
|
struct block *b;
|
|
int regno = alloc_reg();
|
|
|
|
free_reg(index->regno);
|
|
switch (size) {
|
|
|
|
default:
|
|
error("data size must be 1, 2, or 4");
|
|
|
|
case 1:
|
|
size = BPF_B;
|
|
break;
|
|
|
|
case 2:
|
|
size = BPF_H;
|
|
break;
|
|
|
|
case 4:
|
|
size = BPF_W;
|
|
break;
|
|
}
|
|
switch (proto) {
|
|
default:
|
|
error("unsupported index operation");
|
|
|
|
case Q_LINK:
|
|
s = xfer_to_x(index);
|
|
tmp = new_stmt(BPF_LD|BPF_IND|size);
|
|
sappend(s, tmp);
|
|
sappend(index->s, s);
|
|
break;
|
|
|
|
case Q_IP:
|
|
case Q_ARP:
|
|
case Q_RARP:
|
|
/* XXX Note that we assume a fixed link link header here. */
|
|
s = xfer_to_x(index);
|
|
tmp = new_stmt(BPF_LD|BPF_IND|size);
|
|
tmp->s.k = off_nl;
|
|
sappend(s, tmp);
|
|
sappend(index->s, s);
|
|
|
|
b = gen_proto_abbrev(proto);
|
|
if (index->b)
|
|
gen_and(index->b, b);
|
|
index->b = b;
|
|
break;
|
|
|
|
case Q_TCP:
|
|
case Q_UDP:
|
|
case Q_ICMP:
|
|
s = new_stmt(BPF_LDX|BPF_MSH|BPF_B);
|
|
s->s.k = off_nl;
|
|
sappend(s, xfer_to_a(index));
|
|
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_nl;
|
|
sappend(index->s, s);
|
|
|
|
gen_and(gen_proto_abbrev(proto), b = gen_ipfrag());
|
|
if (index->b)
|
|
gen_and(index->b, b);
|
|
index->b = b;
|
|
break;
|
|
}
|
|
index->regno = regno;
|
|
s = new_stmt(BPF_ST);
|
|
s->s.k = regno;
|
|
sappend(index->s, s);
|
|
|
|
return index;
|
|
}
|
|
|
|
struct block *
|
|
gen_relation(code, a0, a1, reversed)
|
|
int code;
|
|
struct arth *a0, *a1;
|
|
int reversed;
|
|
{
|
|
struct slist *s0, *s1, *s2;
|
|
struct block *b, *tmp;
|
|
|
|
s0 = xfer_to_x(a1);
|
|
s1 = xfer_to_a(a0);
|
|
s2 = new_stmt(BPF_ALU|BPF_SUB|BPF_X);
|
|
b = new_block(JMP(code));
|
|
if (reversed)
|
|
gen_not(b);
|
|
|
|
sappend(s1, s2);
|
|
sappend(s0, s1);
|
|
sappend(a1->s, s0);
|
|
sappend(a0->s, a1->s);
|
|
|
|
b->stmts = a0->s;
|
|
|
|
free_reg(a0->regno);
|
|
free_reg(a1->regno);
|
|
|
|
/* 'and' together protocol checks */
|
|
if (a0->b) {
|
|
if (a1->b) {
|
|
gen_and(a0->b, tmp = a1->b);
|
|
}
|
|
else
|
|
tmp = a0->b;
|
|
} else
|
|
tmp = a1->b;
|
|
|
|
if (tmp)
|
|
gen_and(tmp, b);
|
|
|
|
return b;
|
|
}
|
|
|
|
struct arth *
|
|
gen_loadlen()
|
|
{
|
|
int regno = alloc_reg();
|
|
struct arth *a = (struct arth *)newchunk(sizeof(*a));
|
|
struct slist *s;
|
|
|
|
s = new_stmt(BPF_LD|BPF_LEN);
|
|
s->next = new_stmt(BPF_ST);
|
|
s->next->s.k = regno;
|
|
a->s = s;
|
|
a->regno = regno;
|
|
|
|
return a;
|
|
}
|
|
|
|
struct arth *
|
|
gen_loadi(val)
|
|
int val;
|
|
{
|
|
struct arth *a;
|
|
struct slist *s;
|
|
int reg;
|
|
|
|
a = (struct arth *)newchunk(sizeof(*a));
|
|
|
|
reg = alloc_reg();
|
|
|
|
s = new_stmt(BPF_LD|BPF_IMM);
|
|
s->s.k = val;
|
|
s->next = new_stmt(BPF_ST);
|
|
s->next->s.k = reg;
|
|
a->s = s;
|
|
a->regno = reg;
|
|
|
|
return a;
|
|
}
|
|
|
|
struct arth *
|
|
gen_neg(a)
|
|
struct arth *a;
|
|
{
|
|
struct slist *s;
|
|
|
|
s = xfer_to_a(a);
|
|
sappend(a->s, s);
|
|
s = new_stmt(BPF_ALU|BPF_NEG);
|
|
s->s.k = 0;
|
|
sappend(a->s, s);
|
|
s = new_stmt(BPF_ST);
|
|
s->s.k = a->regno;
|
|
sappend(a->s, s);
|
|
|
|
return a;
|
|
}
|
|
|
|
struct arth *
|
|
gen_arth(code, a0, a1)
|
|
int code;
|
|
struct arth *a0, *a1;
|
|
{
|
|
struct slist *s0, *s1, *s2;
|
|
|
|
s0 = xfer_to_x(a1);
|
|
s1 = xfer_to_a(a0);
|
|
s2 = new_stmt(BPF_ALU|BPF_X|code);
|
|
|
|
sappend(s1, s2);
|
|
sappend(s0, s1);
|
|
sappend(a1->s, s0);
|
|
sappend(a0->s, a1->s);
|
|
|
|
free_reg(a1->regno);
|
|
|
|
s0 = new_stmt(BPF_ST);
|
|
a0->regno = s0->s.k = alloc_reg();
|
|
sappend(a0->s, s0);
|
|
|
|
return a0;
|
|
}
|
|
|
|
/*
|
|
* Here we handle simple allocation of the scratch registers.
|
|
* If too many registers are alloc'd, the allocator punts.
|
|
*/
|
|
static int regused[BPF_MEMWORDS];
|
|
static int curreg;
|
|
|
|
/*
|
|
* Return the next free register.
|
|
*/
|
|
static int
|
|
alloc_reg()
|
|
{
|
|
int n = BPF_MEMWORDS;
|
|
|
|
while (--n >= 0) {
|
|
if (regused[curreg])
|
|
curreg = (curreg + 1) % BPF_MEMWORDS;
|
|
else {
|
|
regused[curreg] = 1;
|
|
return curreg;
|
|
}
|
|
}
|
|
error("too many registers needed to evaluate expression");
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
/*
|
|
* Return a register to the table so it can
|
|
* be used later.
|
|
*/
|
|
static void
|
|
free_reg(n)
|
|
int n;
|
|
{
|
|
regused[n] = 0;
|
|
}
|
|
|
|
static struct block *
|
|
gen_len(jmp, n)
|
|
int jmp;
|
|
int n;
|
|
{
|
|
struct slist *s;
|
|
struct block *b;
|
|
|
|
s = new_stmt(BPF_LD|BPF_LEN);
|
|
s->next = new_stmt(BPF_SUB|BPF_IMM);
|
|
s->next->s.k = n;
|
|
b = new_block(JMP(jmp));
|
|
b->stmts = s;
|
|
|
|
return b;
|
|
}
|
|
|
|
struct block *
|
|
gen_greater(n)
|
|
int n;
|
|
{
|
|
return gen_len(BPF_JGE, n);
|
|
}
|
|
|
|
struct block *
|
|
gen_less(n)
|
|
int n;
|
|
{
|
|
struct block *b;
|
|
|
|
b = gen_len(BPF_JGT, n);
|
|
gen_not(b);
|
|
|
|
return b;
|
|
}
|
|
|
|
struct block *
|
|
gen_byteop(op, idx, val)
|
|
int op;
|
|
int idx;
|
|
int val;
|
|
{
|
|
struct block *b;
|
|
struct slist *s;
|
|
|
|
switch (op) {
|
|
default:
|
|
abort();
|
|
|
|
case '=':
|
|
return gen_cmp((u_int)idx, BPF_B, (long)val);
|
|
|
|
case '<':
|
|
b = gen_cmp((u_int)idx, BPF_B, (long)val);
|
|
b->s.code = JMP(BPF_JGE);
|
|
gen_not(b);
|
|
return b;
|
|
|
|
case '>':
|
|
b = gen_cmp((u_int)idx, BPF_B, (long)val);
|
|
b->s.code = JMP(BPF_JGT);
|
|
return b;
|
|
|
|
case '|':
|
|
s = new_stmt(BPF_ALU|BPF_AND|BPF_K);
|
|
break;
|
|
|
|
case '&':
|
|
s = new_stmt(BPF_ALU|BPF_AND|BPF_K);
|
|
break;
|
|
}
|
|
s->s.k = val;
|
|
b = new_block(JMP(BPF_JEQ));
|
|
b->stmts = s;
|
|
gen_not(b);
|
|
|
|
return b;
|
|
}
|
|
|
|
struct block *
|
|
gen_broadcast(proto)
|
|
int proto;
|
|
{
|
|
u_long hostmask;
|
|
struct block *b0, *b1, *b2;
|
|
static u_char ebroadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
|
|
|
|
switch (proto) {
|
|
|
|
case Q_DEFAULT:
|
|
case Q_LINK:
|
|
if (linktype == DLT_EN10MB)
|
|
return gen_ehostop(ebroadcast, Q_DST);
|
|
error("not a broadcast link");
|
|
break;
|
|
|
|
case Q_IP:
|
|
b0 = gen_linktype(ETHERTYPE_IP);
|
|
hostmask = ~netmask;
|
|
b1 = gen_mcmp(off_nl + 16, BPF_W, (long)0, hostmask);
|
|
b2 = gen_mcmp(off_nl + 16, BPF_W,
|
|
(long)(~0 & hostmask), hostmask);
|
|
gen_or(b1, b2);
|
|
gen_and(b0, b2);
|
|
return b2;
|
|
}
|
|
error("only ether/ip broadcast filters supported");
|
|
}
|
|
|
|
struct block *
|
|
gen_multicast(proto)
|
|
int proto;
|
|
{
|
|
register struct block *b0, *b1, *b2;
|
|
register struct slist *s;
|
|
|
|
switch (proto) {
|
|
|
|
case Q_DEFAULT:
|
|
case Q_LINK:
|
|
if (linktype != DLT_EN10MB)
|
|
break;
|
|
|
|
/* ether[0] & 1 != 0 */
|
|
s = new_stmt(BPF_LD|BPF_B|BPF_ABS);
|
|
s->s.k = 0;
|
|
b0 = new_block(JMP(BPF_JSET));
|
|
b0->s.k = 1;
|
|
b0->stmts = s;
|
|
return b0;
|
|
|
|
case Q_IP:
|
|
b0 = gen_linktype(ETHERTYPE_IP);
|
|
b1 = gen_cmp(off_nl + 16, BPF_B, (long)224);
|
|
b1->s.code = JMP(BPF_JGE);
|
|
gen_and(b0, b1);
|
|
return b1;
|
|
}
|
|
error("only ether/ip multicast filters supported");
|
|
}
|