diff options
Diffstat (limited to '')
| -rw-r--r-- | lib/dns/tcpmsg.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/lib/dns/tcpmsg.c b/lib/dns/tcpmsg.c new file mode 100644 index 0000000..44694d8 --- /dev/null +++ b/lib/dns/tcpmsg.c @@ -0,0 +1,236 @@ +/* + * Copyright (C) Internet Systems Consortium, Inc. ("ISC") + * + * SPDX-License-Identifier: MPL-2.0 + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, you can obtain one at https://mozilla.org/MPL/2.0/. + * + * See the COPYRIGHT file distributed with this work for additional + * information regarding copyright ownership. + */ + +/*! \file */ + +#include <inttypes.h> + +#include <isc/mem.h> +#include <isc/print.h> +#include <isc/task.h> +#include <isc/util.h> + +#include <dns/events.h> +#include <dns/result.h> +#include <dns/tcpmsg.h> + +#ifdef TCPMSG_DEBUG +#include <stdio.h> /* Required for printf. */ +#define XDEBUG(x) printf x +#else /* ifdef TCPMSG_DEBUG */ +#define XDEBUG(x) +#endif /* ifdef TCPMSG_DEBUG */ + +#define TCPMSG_MAGIC ISC_MAGIC('T', 'C', 'P', 'm') +#define VALID_TCPMSG(foo) ISC_MAGIC_VALID(foo, TCPMSG_MAGIC) + +static void +recv_length(isc_task_t *, isc_event_t *); +static void +recv_message(isc_task_t *, isc_event_t *); + +static void +recv_length(isc_task_t *task, isc_event_t *ev_in) { + isc_socketevent_t *ev = (isc_socketevent_t *)ev_in; + isc_event_t *dev; + dns_tcpmsg_t *tcpmsg = ev_in->ev_arg; + isc_region_t region; + isc_result_t result; + + INSIST(VALID_TCPMSG(tcpmsg)); + + dev = &tcpmsg->event; + tcpmsg->address = ev->address; + + if (ev->result != ISC_R_SUCCESS) { + tcpmsg->result = ev->result; + goto send_and_free; + } + + /* + * Success. + */ + tcpmsg->size = ntohs(tcpmsg->size); + if (tcpmsg->size == 0) { + tcpmsg->result = ISC_R_UNEXPECTEDEND; + goto send_and_free; + } + if (tcpmsg->size > tcpmsg->maxsize) { + tcpmsg->result = ISC_R_RANGE; + goto send_and_free; + } + + region.base = isc_mem_get(tcpmsg->mctx, tcpmsg->size); + region.length = tcpmsg->size; + if (region.base == NULL) { + tcpmsg->result = ISC_R_NOMEMORY; + goto send_and_free; + } + XDEBUG(("Allocated %d bytes\n", tcpmsg->size)); + + isc_buffer_init(&tcpmsg->buffer, region.base, region.length); + result = isc_socket_recv(tcpmsg->sock, ®ion, 0, task, recv_message, + tcpmsg); + if (result != ISC_R_SUCCESS) { + tcpmsg->result = result; + goto send_and_free; + } + + isc_event_free(&ev_in); + return; + +send_and_free: + isc_task_send(tcpmsg->task, &dev); + tcpmsg->task = NULL; + isc_event_free(&ev_in); + return; +} + +static void +recv_message(isc_task_t *task, isc_event_t *ev_in) { + isc_socketevent_t *ev = (isc_socketevent_t *)ev_in; + isc_event_t *dev; + dns_tcpmsg_t *tcpmsg = ev_in->ev_arg; + + (void)task; + + INSIST(VALID_TCPMSG(tcpmsg)); + + dev = &tcpmsg->event; + tcpmsg->address = ev->address; + + if (ev->result != ISC_R_SUCCESS) { + tcpmsg->result = ev->result; + goto send_and_free; + } + + tcpmsg->result = ISC_R_SUCCESS; + isc_buffer_add(&tcpmsg->buffer, ev->n); + + XDEBUG(("Received %u bytes (of %d)\n", ev->n, tcpmsg->size)); + +send_and_free: + isc_task_send(tcpmsg->task, &dev); + tcpmsg->task = NULL; + isc_event_free(&ev_in); +} + +void +dns_tcpmsg_init(isc_mem_t *mctx, isc_socket_t *sock, dns_tcpmsg_t *tcpmsg) { + REQUIRE(mctx != NULL); + REQUIRE(sock != NULL); + REQUIRE(tcpmsg != NULL); + + tcpmsg->magic = TCPMSG_MAGIC; + tcpmsg->size = 0; + tcpmsg->buffer.base = NULL; + tcpmsg->buffer.length = 0; + tcpmsg->maxsize = 65535; /* Largest message possible. */ + tcpmsg->mctx = mctx; + tcpmsg->sock = sock; + tcpmsg->task = NULL; /* None yet. */ + tcpmsg->result = ISC_R_UNEXPECTED; /* None yet. */ + + /* Should probably initialize the event here, but it can wait. */ +} + +void +dns_tcpmsg_setmaxsize(dns_tcpmsg_t *tcpmsg, unsigned int maxsize) { + REQUIRE(VALID_TCPMSG(tcpmsg)); + REQUIRE(maxsize < 65536); + + tcpmsg->maxsize = maxsize; +} + +isc_result_t +dns_tcpmsg_readmessage(dns_tcpmsg_t *tcpmsg, isc_task_t *task, + isc_taskaction_t action, void *arg) { + isc_result_t result; + isc_region_t region; + + REQUIRE(VALID_TCPMSG(tcpmsg)); + REQUIRE(task != NULL); + REQUIRE(tcpmsg->task == NULL); /* not currently in use */ + + if (tcpmsg->buffer.base != NULL) { + isc_mem_put(tcpmsg->mctx, tcpmsg->buffer.base, + tcpmsg->buffer.length); + tcpmsg->buffer.base = NULL; + tcpmsg->buffer.length = 0; + } + + tcpmsg->task = task; + tcpmsg->action = action; + tcpmsg->arg = arg; + tcpmsg->result = ISC_R_UNEXPECTED; /* unknown right now */ + + ISC_EVENT_INIT(&tcpmsg->event, sizeof(isc_event_t), 0, 0, + DNS_EVENT_TCPMSG, action, arg, tcpmsg, NULL, NULL); + + region.base = (unsigned char *)&tcpmsg->size; + region.length = 2; /* uint16_t */ + result = isc_socket_recv(tcpmsg->sock, ®ion, 0, tcpmsg->task, + recv_length, tcpmsg); + + if (result != ISC_R_SUCCESS) { + tcpmsg->task = NULL; + } + + return (result); +} + +void +dns_tcpmsg_cancelread(dns_tcpmsg_t *tcpmsg) { + REQUIRE(VALID_TCPMSG(tcpmsg)); + + isc_socket_cancel(tcpmsg->sock, NULL, ISC_SOCKCANCEL_RECV); +} + +void +dns_tcpmsg_keepbuffer(dns_tcpmsg_t *tcpmsg, isc_buffer_t *buffer) { + REQUIRE(VALID_TCPMSG(tcpmsg)); + REQUIRE(buffer != NULL); + + *buffer = tcpmsg->buffer; + tcpmsg->buffer.base = NULL; + tcpmsg->buffer.length = 0; +} + +#if 0 +void +dns_tcpmsg_freebuffer(dns_tcpmsg_t *tcpmsg) { + REQUIRE(VALID_TCPMSG(tcpmsg)); + + if (tcpmsg->buffer.base == NULL) { + return; + } + + isc_mem_put(tcpmsg->mctx, tcpmsg->buffer.base, tcpmsg->buffer.length); + tcpmsg->buffer.base = NULL; + tcpmsg->buffer.length = 0; +} +#endif /* if 0 */ + +void +dns_tcpmsg_invalidate(dns_tcpmsg_t *tcpmsg) { + REQUIRE(VALID_TCPMSG(tcpmsg)); + + tcpmsg->magic = 0; + + if (tcpmsg->buffer.base != NULL) { + isc_mem_put(tcpmsg->mctx, tcpmsg->buffer.base, + tcpmsg->buffer.length); + tcpmsg->buffer.base = NULL; + tcpmsg->buffer.length = 0; + } +} |