/*
* m_ematch.c Extended Matches
*
* This program is free software; you can distribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Authors: Thomas Graf <tgraf@suug.ch>
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <string.h>
#include <dlfcn.h>
#include <stdarg.h>
#include <errno.h>
#include "utils.h"
#include "tc_util.h"
#include "m_ematch.h"
#define EMATCH_MAP "/etc/iproute2/ematch_map"
static struct ematch_util *ematch_list;
/* export to bison parser */
int ematch_argc;
char **ematch_argv;
char *ematch_err;
struct ematch *ematch_root;
static int begin_argc;
static char **begin_argv;
static void bstr_print(FILE *fd, const struct bstr *b, int ascii);
static inline void map_warning(int num, char *kind)
{
fprintf(stderr,
"Error: Unable to find ematch \"%s\" in %s\n" \
"Please assign a unique ID to the ematch kind the suggested " \
"entry is:\n" \
"\t%d\t%s\n",
kind, EMATCH_MAP, num, kind);
}
static int lookup_map(__u16 num, char *dst, int len, const char *file)
{
int err = -EINVAL;
char buf[512];
FILE *fd = fopen(file, "r");
if (fd == NULL)
return -errno;
while (fgets(buf, sizeof(buf), fd)) {
char namebuf[512], *p = buf;
int id;
while (*p == ' ' || *p == '\t')
p++;
if (*p == '#' || *p == '\n' || *p == 0)
continue;
if (sscanf(p, "%d %s", &id, namebuf) != 2) {
fprintf(stderr, "ematch map %s corrupted at %s\n",
file, p);
goto out;
}
if (id == num) {
if (dst)
strncpy(dst, namebuf, len - 1);
err = 0;
goto out;
}
}
err = -ENOENT;
out:
fclose(fd);
return err;
}
static int lookup_map_id(char *kind, int *dst, const char *file)
{
int err = -EINVAL;
char buf[512];
FILE *fd = fopen(file, "r");
if (fd == NULL)
return -errno;
while (fgets(buf, sizeof(buf), fd)) {
char namebuf[512], *p = buf;
int id;
while (*p == ' ' || *p == '\t')
p++;
if (*p == '#' || *p == '\n' || *p == 0)
continue;
if (sscanf(p, "%d %s", &id, namebuf) != 2) {
fprintf(stderr, "ematch map %s corrupted at %s\n",
file, p);
goto out;
}
if (!strcasecmp(namebuf, kind)) {
if (dst)
*dst = id;
err = 0;
goto out;
}
}
err = -ENOENT;
*dst = 0;
out:
fclose(fd);
return err;
}
static struct ematch_util *get_ematch_kind(char *kind)
{
static void *body;
void *dlh;
char buf[256];
struct ematch_util *e;
for (e = ematch_list; e; e = e->next) {
if (strcmp(e->kind, kind) == 0)
return e;
}
snprintf(buf, sizeof(buf), "em_%s.so", kind);
dlh = dlopen(buf, RTLD_LAZY);
if (dlh == NULL) {
dlh = body;
if (dlh == NULL) {
dlh = body = dlopen(NULL, RTLD_LAZY);
if (dlh == NULL)
return NULL;
}
}
snprintf(buf, sizeof(buf), "%s_ematch_util", kind);
e = dlsym(dlh, buf);
if (e == NULL)
return NULL;
e->next = ematch_list;
ematch_list = e;
return e;
}
static struct ematch_util *get_ematch_kind_num(__u16 kind)
{
char name[513];
if (lookup_map(kind, name, sizeof(name), EMATCH_MAP) < 0)
return NULL;
return get_ematch_kind(name);
}
static int em_parse_call(struct nlmsghdr *n, struct tcf_ematch_hdr *hdr,
struct ematch_util *e, struct ematch *t)
{
if (e->parse_eopt_argv) {
int argc = 0, i = 0, ret;
struct bstr *args;
char **argv;
for (args = t->args; args; args = bstr_next(args))
argc++;
argv = calloc(argc, sizeof(char *));
if (!argv)
return -1;
for (args = t->args; args; args = bstr_next(args))
argv[i++] = args->data;
ret = e->parse_eopt_argv(n, hdr, argc, argv);
free(argv);
return ret;
}
return e->parse_eopt(n, hdr, t->args->next);
}
static int parse_tree(struct nlmsghdr *n, struct ematch *tree)
{
int index = 1;
struct ematch *t;
for (t = tree; t; t = t->next) {
struct rtattr *tail;
struct tcf_ematch_hdr hdr = { .flags = t->relation };
if (t->inverted)
hdr.flags |= TCF_EM_INVERT;
tail = addattr_nest(n, MAX_MSG, index++);
if (t->child) {
__u32 r = t->child_ref;
addraw_l(n, MAX_MSG, &hdr, sizeof(hdr));
addraw_l(n, MAX_MSG, &r, sizeof(r));
} else {
int num = 0, err;
char buf[64];
struct ematch_util *e;
if (t->args == NULL)
return -1;
strncpy(buf, (char *) t->args->data, sizeof(buf)-1);
e = get_ematch_kind(buf);
if (e == NULL) {
fprintf(stderr, "Unknown ematch \"%s\"\n",
buf);
return -1;
}
err = lookup_map_id(buf, &num, EMATCH_MAP);
if (err < 0) {
if (err == -ENOENT)
map_warning(e->kind_num, buf);
return err;
}
hdr.kind = num;
if (em_parse_call(n, &hdr, e, t) < 0)
return -1;
}
addattr_nest_end(n, tail);
}
return 0;
}
static int flatten_tree(struct ematch *head, struct ematch *tree)
{
int i, count = 0;
struct ematch *t;
for (;;) {
count++;
if (tree->child) {
for (t = head; t->next; t = t->next);
t->next = tree->child;
count += flatten_tree(head, tree->child);
}
if (tree->relation == 0)
break;
tree = tree->next;
}
for (i = 0, t = head; t; t = t->next, i++)
t->index = i;
for (t = head; t; t = t->next)
if (t->child)
t->child_ref = t->child->index;
return count;
}
__attribute__((format(printf, 5, 6)))
int em_parse_error(int err, struct bstr *args, struct bstr *carg,
struct ematch_util *e, char *fmt, ...)
{
va_list a;
va_start(a, fmt);
vfprintf(stderr, fmt, a);
va_end(a);
if (ematch_err)
fprintf(stderr, ": %s\n... ", ematch_err);
else
fprintf(stderr, "\n... ");
while (ematch_argc < begin_argc) {
if (ematch_argc == (begin_argc - 1))
fprintf(stderr, ">>%s<< ", *begin_argv);
else
fprintf(stderr, "%s ", *begin_argv);
begin_argv++;
begin_argc--;
}
fprintf(stderr, "...\n");
if (args) {
fprintf(stderr, "... %s(", e->kind);
while (args) {
fprintf(stderr, "%s", args == carg ? ">>" : "");
bstr_print(stderr, args, 1);
fprintf(stderr, "%s%s", args == carg ? "<<" : "",
args->next ? " " : "");
args = args->next;
}
fprintf(stderr, ")...\n");
}
if (e == NULL) {
fprintf(stderr,
"Usage: EXPR\n" \
"where: EXPR := TERM [ { and | or } EXPR ]\n" \
" TERM := [ not ] { MATCH | '(' EXPR ')' }\n" \
" MATCH := module '(' ARGS ')'\n" \
" ARGS := ARG1 ARG2 ...\n" \
"\n" \
"Example: a(x y) and not (b(x) or c(x y z))\n");
} else
e->print_usage(stderr);
return -err;
}
static inline void free_ematch_err(void)
{
if (ematch_err) {
free(ematch_err);
ematch_err = NULL;
}
}
extern int ematch_parse(void);
int parse_ematch(int *argc_p, char ***argv_p, int tca_id, struct nlmsghdr *n)
{
begin_argc = ematch_argc = *argc_p;
begin_argv = ematch_argv = *argv_p;
if (ematch_parse()) {
int err = em_parse_error(EINVAL, NULL, NULL, NULL,
"Parse error");
free_ematch_err();
return err;
}
free_ematch_err();
/* undo look ahead by parser */
ematch_argc++;
ematch_argv--;
if (ematch_root) {
struct rtattr *tail, *tail_list;
struct tcf_ematch_tree_hdr hdr = {
.nmatches = flatten_tree(ematch_root, ematch_root),
.progid = TCF_EM_PROG_TC
};
tail = addattr_nest(n, MAX_MSG, tca_id);
addattr_l(n, MAX_MSG, TCA_EMATCH_TREE_HDR, &hdr, sizeof(hdr));
tail_list = addattr_nest(n, MAX_MSG, TCA_EMATCH_TREE_LIST);
if (parse_tree(n, ematch_root) < 0)
return -1;
addattr_nest_end(n, tail_list);
addattr_nest_end(n, tail);
}
*argc_p = ematch_argc;
*argv_p = ematch_argv;
return 0;
}
static int print_ematch_seq(FILE *fd, struct rtattr **tb, int start,
int prefix)
{
int n, i = start;
struct tcf_ematch_hdr *hdr;
int dlen;
void *data;
for (;;) {
if (tb[i] == NULL)
return -1;
dlen = RTA_PAYLOAD(tb[i]) - sizeof(*hdr);
data = (void *) RTA_DATA(tb[i]) + sizeof(*hdr);
if (dlen < 0)
return -1;
hdr = RTA_DATA(tb[i]);
if (hdr->flags & TCF_EM_INVERT)
fprintf(fd, "NOT ");
if (hdr->kind == 0) {
__u32 ref;
if (dlen < sizeof(__u32))
return -1;
ref = *(__u32 *) data;
fprintf(fd, "(\n");
for (n = 0; n <= prefix; n++)
fprintf(fd, " ");
if (print_ematch_seq(fd, tb, ref + 1, prefix + 1) < 0)
return -1;
for (n = 0; n < prefix; n++)
fprintf(fd, " ");
fprintf(fd, ") ");
} else {
struct ematch_util *e;
e = get_ematch_kind_num(hdr->kind);
if (e == NULL)
fprintf(fd, "[unknown ematch %d]\n",
hdr->kind);
else {
fprintf(fd, "%s(", e->kind);
if (e->print_eopt(fd, hdr, data, dlen) < 0)
return -1;
fprintf(fd, ")\n");
}
if (hdr->flags & TCF_EM_REL_MASK)
for (n = 0; n < prefix; n++)
fprintf(fd, " ");
}
switch (hdr->flags & TCF_EM_REL_MASK) {
case TCF_EM_REL_AND:
fprintf(fd, "AND ");
break;
case TCF_EM_REL_OR:
fprintf(fd, "OR ");
break;
default:
return 0;
}
i++;
}
return 0;
}
static int print_ematch_list(FILE *fd, struct tcf_ematch_tree_hdr *hdr,
struct rtattr *rta)
{
int err = -1;
struct rtattr **tb;
tb = malloc((hdr->nmatches + 1) * sizeof(struct rtattr *));
if (tb == NULL)
return -1;
if (hdr->nmatches > 0) {
if (parse_rtattr_nested(tb, hdr->nmatches, rta) < 0)
goto errout;
fprintf(fd, "\n ");
if (print_ematch_seq(fd, tb, 1, 1) < 0)
goto errout;
}
err = 0;
errout:
free(tb);
return err;
}
int print_ematch(FILE *fd, const struct rtattr *rta)
{
struct rtattr *tb[TCA_EMATCH_TREE_MAX+1];
struct tcf_ematch_tree_hdr *hdr;
if (parse_rtattr_nested(tb, TCA_EMATCH_TREE_MAX, rta) < 0)
return -1;
if (tb[TCA_EMATCH_TREE_HDR] == NULL) {
fprintf(stderr, "Missing ematch tree header\n");
return -1;
}
if (tb[TCA_EMATCH_TREE_LIST] == NULL) {
fprintf(stderr, "Missing ematch tree list\n");
return -1;
}
if (RTA_PAYLOAD(tb[TCA_EMATCH_TREE_HDR]) < sizeof(*hdr)) {
fprintf(stderr, "Ematch tree header size mismatch\n");
return -1;
}
hdr = RTA_DATA(tb[TCA_EMATCH_TREE_HDR]);
return print_ematch_list(fd, hdr, tb[TCA_EMATCH_TREE_LIST]);
}
struct bstr *bstr_alloc(const char *text)
{
struct bstr *b = calloc(1, sizeof(*b));
if (b == NULL)
return NULL;
b->data = strdup(text);
if (b->data == NULL) {
free(b);
return NULL;
}
b->len = strlen(text);
return b;
}
unsigned long bstrtoul(const struct bstr *b)
{
char *inv = NULL;
unsigned long l;
char buf[b->len+1];
memcpy(buf, b->data, b->len);
buf[b->len] = '\0';
l = strtoul(buf, &inv, 0);
if (l == ULONG_MAX || inv == buf)
return ULONG_MAX;
return l;
}
static void bstr_print(FILE *fd, const struct bstr *b, int ascii)
{
int i;
char *s = b->data;
if (ascii)
for (i = 0; i < b->len; i++)
fprintf(fd, "%c", isprint(s[i]) ? s[i] : '.');
else {
for (i = 0; i < b->len; i++)
fprintf(fd, "%02x", s[i]);
fprintf(fd, "\"");
for (i = 0; i < b->len; i++)
fprintf(fd, "%c", isprint(s[i]) ? s[i] : '.');
fprintf(fd, "\"");
}
}