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/* Copyright (C) 2022 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <signal.h>
#include "knot/server/udp-handler.c"
#include "knot/common/log.h"
typedef struct {
struct iovec iov[NBUFS];
uint8_t buf[NBUFS][KNOT_WIRE_MAX_PKTSIZE];
struct sockaddr_storage addr;
bool afl_persistent;
} udp_stdin_t;
static inline void next(udp_stdin_t *rq)
{
if (rq->afl_persistent) {
raise(SIGSTOP);
} else {
exit(0);
}
}
static void *udp_stdin_init(_unused_ udp_context_t *ctx, _unused_ void *xdp_sock)
{
udp_stdin_t *rq = calloc(1, sizeof(udp_stdin_t));
if (rq == NULL) {
return NULL;
}
for (unsigned i = 0; i < NBUFS; ++i) {
rq->iov[i].iov_base = rq->buf[i];
rq->iov[i].iov_len = KNOT_WIRE_MAX_PKTSIZE;
}
struct sockaddr_in *a = (struct sockaddr_in *)&rq->addr;
a->sin_family = AF_INET;
a->sin_addr.s_addr = IN_LOOPBACKNET;
a->sin_port = 42;
rq->afl_persistent = getenv("AFL_PERSISTENT") != NULL;
return rq;
}
static void udp_stdin_deinit(void *d)
{
free(d);
}
static int udp_stdin_recv(_unused_ int fd, void *d)
{
udp_stdin_t *rq = (udp_stdin_t *)d;
rq->iov[RX].iov_len = fread(rq->iov[RX].iov_base, 1,
KNOT_WIRE_MAX_PKTSIZE, stdin);
if (rq->iov[RX].iov_len == 0) {
next(rq);
}
return rq->iov[RX].iov_len;
}
static void udp_stdin_handle(udp_context_t *ctx, void *d)
{
udp_stdin_t *rq = (udp_stdin_t *)d;
udp_handle(ctx, STDIN_FILENO, &rq->addr, &rq->iov[RX], &rq->iov[TX], false);
}
static void udp_stdin_send(void *d)
{
udp_stdin_t *rq = (udp_stdin_t *)d;
next(rq);
}
static udp_api_t stdin_api = {
udp_stdin_init,
udp_stdin_deinit,
udp_stdin_recv,
udp_stdin_handle,
udp_stdin_send
};
void udp_master_init_stdio(server_t *server) {
log_info("AFL, UDP handler listening on stdin");
// Register dummy interface to server.
iface_t *ifc = calloc(1, sizeof(*ifc));
assert(ifc);
ifc->fd_udp = calloc(1, sizeof(*ifc->fd_udp));
assert(ifc->fd_udp);
ifc->fd_udp[0] = STDIN_FILENO;
ifc->fd_udp_count = 1;
server->n_ifaces = 1;
server->ifaces = ifc;
udp_recvfrom_api = stdin_api;
#ifdef ENABLE_RECVMMSG
udp_recvmmsg_api = stdin_api;
#endif
}
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