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571 lines
11 KiB
571 lines
11 KiB
/*
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* m_ematch.c Extended Matches
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*
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* This program is free software; you can distribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Authors: Thomas Graf <tgraf@suug.ch>
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <syslog.h>
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#include <fcntl.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <string.h>
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#include <dlfcn.h>
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#include <stdarg.h>
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#include <errno.h>
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#include "utils.h"
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#include "tc_util.h"
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#include "m_ematch.h"
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#define EMATCH_MAP "/etc/iproute2/ematch_map"
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static struct ematch_util *ematch_list;
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/* export to bison parser */
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int ematch_argc;
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char **ematch_argv;
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char *ematch_err;
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struct ematch *ematch_root;
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static int begin_argc;
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static char **begin_argv;
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static inline void map_warning(int num, char *kind)
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{
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fprintf(stderr,
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"Error: Unable to find ematch \"%s\" in %s\n" \
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"Please assign a unique ID to the ematch kind the suggested " \
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"entry is:\n" \
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"\t%d\t%s\n",
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kind, EMATCH_MAP, num, kind);
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}
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static int lookup_map(__u16 num, char *dst, int len, const char *file)
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{
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int err = -EINVAL;
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char buf[512];
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FILE *fd = fopen(file, "r");
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if (fd == NULL)
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return -errno;
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while (fgets(buf, sizeof(buf), fd)) {
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char namebuf[512], *p = buf;
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int id;
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while (*p == ' ' || *p == '\t')
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p++;
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if (*p == '#' || *p == '\n' || *p == 0)
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continue;
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if (sscanf(p, "%d %s", &id, namebuf) != 2) {
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fprintf(stderr, "ematch map %s corrupted at %s\n",
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file, p);
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goto out;
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}
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if (id == num) {
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if (dst)
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strncpy(dst, namebuf, len - 1);
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err = 0;
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goto out;
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}
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}
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err = -ENOENT;
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out:
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fclose(fd);
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return err;
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}
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static int lookup_map_id(char *kind, int *dst, const char *file)
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{
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int err = -EINVAL;
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char buf[512];
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FILE *fd = fopen(file, "r");
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if (fd == NULL)
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return -errno;
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while (fgets(buf, sizeof(buf), fd)) {
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char namebuf[512], *p = buf;
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int id;
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while (*p == ' ' || *p == '\t')
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p++;
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if (*p == '#' || *p == '\n' || *p == 0)
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continue;
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if (sscanf(p, "%d %s", &id, namebuf) != 2) {
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fprintf(stderr, "ematch map %s corrupted at %s\n",
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file, p);
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goto out;
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}
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if (!strcasecmp(namebuf, kind)) {
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if (dst)
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*dst = id;
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err = 0;
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goto out;
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}
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}
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err = -ENOENT;
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*dst = 0;
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out:
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fclose(fd);
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return err;
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}
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static struct ematch_util *get_ematch_kind(char *kind)
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{
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static void *body;
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void *dlh;
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char buf[256];
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struct ematch_util *e;
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for (e = ematch_list; e; e = e->next) {
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if (strcmp(e->kind, kind) == 0)
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return e;
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}
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snprintf(buf, sizeof(buf), "em_%s.so", kind);
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dlh = dlopen(buf, RTLD_LAZY);
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if (dlh == NULL) {
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dlh = body;
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if (dlh == NULL) {
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dlh = body = dlopen(NULL, RTLD_LAZY);
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if (dlh == NULL)
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return NULL;
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}
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}
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snprintf(buf, sizeof(buf), "%s_ematch_util", kind);
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e = dlsym(dlh, buf);
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if (e == NULL)
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return NULL;
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e->next = ematch_list;
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ematch_list = e;
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return e;
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}
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static struct ematch_util *get_ematch_kind_num(__u16 kind)
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{
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char name[32];
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if (lookup_map(kind, name, sizeof(name), EMATCH_MAP) < 0)
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return NULL;
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return get_ematch_kind(name);
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}
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static int parse_tree(struct nlmsghdr *n, struct ematch *tree)
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{
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int index = 1;
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struct ematch *t;
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for (t = tree; t; t = t->next) {
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struct rtattr *tail = NLMSG_TAIL(n);
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struct tcf_ematch_hdr hdr = { .flags = t->relation };
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if (t->inverted)
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hdr.flags |= TCF_EM_INVERT;
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addattr_l(n, MAX_MSG, index++, NULL, 0);
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if (t->child) {
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__u32 r = t->child_ref;
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addraw_l(n, MAX_MSG, &hdr, sizeof(hdr));
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addraw_l(n, MAX_MSG, &r, sizeof(r));
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} else {
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int num = 0, err;
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char buf[64];
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struct ematch_util *e;
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if (t->args == NULL)
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return -1;
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strncpy(buf, (char *) t->args->data, sizeof(buf)-1);
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e = get_ematch_kind(buf);
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if (e == NULL) {
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fprintf(stderr, "Unknown ematch \"%s\"\n",
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buf);
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return -1;
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}
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err = lookup_map_id(buf, &num, EMATCH_MAP);
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if (err < 0) {
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if (err == -ENOENT)
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map_warning(e->kind_num, buf);
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return err;
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}
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hdr.kind = num;
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if (e->parse_eopt(n, &hdr, t->args->next) < 0)
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return -1;
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}
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tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
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}
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return 0;
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}
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static int flatten_tree(struct ematch *head, struct ematch *tree)
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{
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int i, count = 0;
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struct ematch *t;
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for (;;) {
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count++;
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if (tree->child) {
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for (t = head; t->next; t = t->next);
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t->next = tree->child;
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count += flatten_tree(head, tree->child);
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}
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if (tree->relation == 0)
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break;
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tree = tree->next;
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}
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for (i = 0, t = head; t; t = t->next, i++)
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t->index = i;
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for (t = head; t; t = t->next)
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if (t->child)
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t->child_ref = t->child->index;
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return count;
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}
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int em_parse_error(int err, struct bstr *args, struct bstr *carg,
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struct ematch_util *e, char *fmt, ...)
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{
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va_list a;
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va_start(a, fmt);
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vfprintf(stderr, fmt, a);
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va_end(a);
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if (ematch_err)
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fprintf(stderr, ": %s\n... ", ematch_err);
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else
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fprintf(stderr, "\n... ");
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while (ematch_argc < begin_argc) {
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if (ematch_argc == (begin_argc - 1))
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fprintf(stderr, ">>%s<< ", *begin_argv);
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else
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fprintf(stderr, "%s ", *begin_argv);
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begin_argv++;
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begin_argc--;
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}
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fprintf(stderr, "...\n");
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if (args) {
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fprintf(stderr, "... %s(", e->kind);
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while (args) {
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fprintf(stderr, "%s", args == carg ? ">>" : "");
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bstr_print(stderr, args, 1);
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fprintf(stderr, "%s%s", args == carg ? "<<" : "",
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args->next ? " " : "");
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args = args->next;
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}
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fprintf(stderr, ")...\n");
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}
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if (e == NULL) {
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fprintf(stderr,
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"Usage: EXPR\n" \
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"where: EXPR := TERM [ { and | or } EXPR ]\n" \
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" TERM := [ not ] { MATCH | '(' EXPR ')' }\n" \
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" MATCH := module '(' ARGS ')'\n" \
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" ARGS := ARG1 ARG2 ...\n" \
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"\n" \
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"Example: a(x y) and not (b(x) or c(x y z))\n");
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} else
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e->print_usage(stderr);
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return -err;
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}
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static inline void free_ematch_err(void)
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{
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if (ematch_err) {
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free(ematch_err);
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ematch_err = NULL;
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}
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}
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extern int ematch_parse(void);
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int parse_ematch(int *argc_p, char ***argv_p, int tca_id, struct nlmsghdr *n)
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{
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begin_argc = ematch_argc = *argc_p;
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begin_argv = ematch_argv = *argv_p;
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if (ematch_parse()) {
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int err = em_parse_error(EINVAL, NULL, NULL, NULL,
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"Parse error");
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free_ematch_err();
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return err;
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}
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free_ematch_err();
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/* undo look ahead by parser */
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ematch_argc++;
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ematch_argv--;
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if (ematch_root) {
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struct rtattr *tail, *tail_list;
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struct tcf_ematch_tree_hdr hdr = {
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.nmatches = flatten_tree(ematch_root, ematch_root),
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.progid = TCF_EM_PROG_TC
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};
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tail = NLMSG_TAIL(n);
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addattr_l(n, MAX_MSG, tca_id, NULL, 0);
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addattr_l(n, MAX_MSG, TCA_EMATCH_TREE_HDR, &hdr, sizeof(hdr));
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tail_list = NLMSG_TAIL(n);
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addattr_l(n, MAX_MSG, TCA_EMATCH_TREE_LIST, NULL, 0);
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if (parse_tree(n, ematch_root) < 0)
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return -1;
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tail_list->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail_list;
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tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
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}
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*argc_p = ematch_argc;
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*argv_p = ematch_argv;
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return 0;
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}
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static int print_ematch_seq(FILE *fd, struct rtattr **tb, int start,
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int prefix)
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{
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int n, i = start;
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struct tcf_ematch_hdr *hdr;
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int dlen;
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void *data;
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for (;;) {
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if (tb[i] == NULL)
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return -1;
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dlen = RTA_PAYLOAD(tb[i]) - sizeof(*hdr);
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data = (void *) RTA_DATA(tb[i]) + sizeof(*hdr);
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if (dlen < 0)
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return -1;
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hdr = RTA_DATA(tb[i]);
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if (hdr->flags & TCF_EM_INVERT)
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fprintf(fd, "NOT ");
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if (hdr->kind == 0) {
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__u32 ref;
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if (dlen < sizeof(__u32))
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return -1;
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ref = *(__u32 *) data;
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fprintf(fd, "(\n");
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for (n = 0; n <= prefix; n++)
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fprintf(fd, " ");
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if (print_ematch_seq(fd, tb, ref + 1, prefix + 1) < 0)
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return -1;
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for (n = 0; n < prefix; n++)
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fprintf(fd, " ");
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fprintf(fd, ") ");
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} else {
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struct ematch_util *e;
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e = get_ematch_kind_num(hdr->kind);
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if (e == NULL)
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fprintf(fd, "[unknown ematch %d]\n",
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hdr->kind);
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else {
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fprintf(fd, "%s(", e->kind);
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if (e->print_eopt(fd, hdr, data, dlen) < 0)
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return -1;
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fprintf(fd, ")\n");
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}
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if (hdr->flags & TCF_EM_REL_MASK)
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for (n = 0; n < prefix; n++)
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fprintf(fd, " ");
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}
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switch (hdr->flags & TCF_EM_REL_MASK) {
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case TCF_EM_REL_AND:
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fprintf(fd, "AND ");
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break;
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case TCF_EM_REL_OR:
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fprintf(fd, "OR ");
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break;
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default:
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return 0;
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}
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i++;
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}
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return 0;
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}
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static int print_ematch_list(FILE *fd, struct tcf_ematch_tree_hdr *hdr,
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struct rtattr *rta)
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{
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int err = -1;
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struct rtattr **tb;
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tb = malloc((hdr->nmatches + 1) * sizeof(struct rtattr *));
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if (tb == NULL)
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return -1;
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if (hdr->nmatches > 0) {
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if (parse_rtattr_nested(tb, hdr->nmatches, rta) < 0)
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goto errout;
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fprintf(fd, "\n ");
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if (print_ematch_seq(fd, tb, 1, 1) < 0)
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goto errout;
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}
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err = 0;
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errout:
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free(tb);
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return err;
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}
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int print_ematch(FILE *fd, const struct rtattr *rta)
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{
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struct rtattr *tb[TCA_EMATCH_TREE_MAX+1];
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struct tcf_ematch_tree_hdr *hdr;
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if (parse_rtattr_nested(tb, TCA_EMATCH_TREE_MAX, rta) < 0)
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return -1;
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if (tb[TCA_EMATCH_TREE_HDR] == NULL) {
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fprintf(stderr, "Missing ematch tree header\n");
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return -1;
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}
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if (tb[TCA_EMATCH_TREE_LIST] == NULL) {
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fprintf(stderr, "Missing ematch tree list\n");
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return -1;
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}
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if (RTA_PAYLOAD(tb[TCA_EMATCH_TREE_HDR]) < sizeof(*hdr)) {
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fprintf(stderr, "Ematch tree header size mismatch\n");
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return -1;
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}
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hdr = RTA_DATA(tb[TCA_EMATCH_TREE_HDR]);
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return print_ematch_list(fd, hdr, tb[TCA_EMATCH_TREE_LIST]);
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}
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struct bstr *bstr_alloc(const char *text)
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{
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struct bstr *b = calloc(1, sizeof(*b));
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|
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if (b == NULL)
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return NULL;
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b->data = strdup(text);
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if (b->data == NULL) {
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free(b);
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return NULL;
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}
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b->len = strlen(text);
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return b;
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}
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unsigned long bstrtoul(const struct bstr *b)
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{
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char *inv = NULL;
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unsigned long l;
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char buf[b->len+1];
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memcpy(buf, b->data, b->len);
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buf[b->len] = '\0';
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l = strtoul(buf, &inv, 0);
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if (l == ULONG_MAX || inv == buf)
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return ULONG_MAX;
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return l;
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}
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void bstr_print(FILE *fd, const struct bstr *b, int ascii)
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{
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int i;
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char *s = b->data;
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if (ascii)
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for (i = 0; i < b->len; i++)
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fprintf(fd, "%c", isprint(s[i]) ? s[i] : '.');
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else {
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for (i = 0; i < b->len; i++)
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fprintf(fd, "%02x", s[i]);
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fprintf(fd, "\"");
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for (i = 0; i < b->len; i++)
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fprintf(fd, "%c", isprint(s[i]) ? s[i] : '.');
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fprintf(fd, "\"");
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}
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}
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void print_ematch_tree(const struct ematch *tree)
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{
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const struct ematch *t;
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for (t = tree; t; t = t->next) {
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if (t->inverted)
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printf("NOT ");
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if (t->child) {
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printf("(");
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print_ematch_tree(t->child);
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printf(")");
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} else {
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struct bstr *b;
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for (b = t->args; b; b = b->next)
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printf("%s%s", b->data, b->next ? " " : "");
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}
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if (t->relation == TCF_EM_REL_AND)
|
|
printf(" AND ");
|
|
else if (t->relation == TCF_EM_REL_OR)
|
|
printf(" OR ");
|
|
}
|
|
}
|