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Creating TCP dispatch now creates/binds the socket

Browse Source 
Previously, creation of TCP dispatches differed from UDP in that a TCP
dispatch was created to attach to an existing socket, whereas a UDP
dispatch would be created in a vacuum and sockets would be opened on
demand when a transaction was initiated.

We are moving as much socket code as possible into the dispatch module,
so that it can be replaced with a netmgr version as easily as
possible. (This will also have the side effect of making TCP and UDP
dispatches more similar.)

As a step in that direction, this commit changes
dns_dispatch_createtcp() so that it creates the TCP socket.
This commit is contained in:
Evan Hunt 2020-12-18 14:59:50 -08:00
parent f439eb5d99
commit 4f30b679e7
4 changed files with 125 additions and 216 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

178
lib/dns/dispatch.c
View File

@ -631,6 +631,7 @@ get_dispsocket(dns_dispatch_t *disp, const isc_sockaddr_t *dest,
continue;
}
UNLOCK(&qid->lock);
result = open_socket(sockmgr, &localaddr,
ISC_SOCKET_REUSEADDRESS, &sock);
if (result == ISC_R_SUCCESS) {
@ -1652,8 +1653,9 @@ qid_destroy(isc_mem_t *mctx, dns_qid_t **qidp) {
/*
* Allocate and set important limits.
*/
static isc_result_t
dispatch_allocate(dns_dispatchmgr_t *mgr, dns_dispatch_t **dispp) {
static void
dispatch_allocate(dns_dispatchmgr_t *mgr, isc_sockettype_t type, int pf,
unsigned int attributes, dns_dispatch_t **dispp) {
dns_dispatch_t *disp = NULL;
REQUIRE(VALID_DISPATCHMGR(mgr));
@ -1668,18 +1670,50 @@ dispatch_allocate(dns_dispatchmgr_t *mgr, dns_dispatch_t **dispp) {
isc_refcount_increment0(&mgr->irefs);
*disp = (dns_dispatch_t){ .mgr = mgr,
.socktype = type,
.shutdown_why = ISC_R_UNEXPECTED };
isc_refcount_init(&disp->refcount, 1);
ISC_LINK_INIT(disp, link);
ISC_LIST_INIT(disp->activesockets);
ISC_LIST_INIT(disp->inactivesockets);
switch (type) {
case isc_sockettype_tcp:
disp->attributes |= DNS_DISPATCHATTR_TCP;
break;
case isc_sockettype_udp:
disp->attributes |= DNS_DISPATCHATTR_UDP;
break;
default:
INSIST(0);
ISC_UNREACHABLE();
}
switch (pf) {
case PF_INET:
disp->attributes |= DNS_DISPATCHATTR_IPV4;
break;
case PF_INET6:
disp->attributes |= DNS_DISPATCHATTR_IPV6;
break;
default:
INSIST(0);
ISC_UNREACHABLE();
}
/*
* Set whatever attributes were passed in that haven't been
* reset automatically by the code above.
*/
attributes &= ~(DNS_DISPATCHATTR_UDP | DNS_DISPATCHATTR_TCP |
DNS_DISPATCHATTR_IPV4 | DNS_DISPATCHATTR_IPV6);
disp->attributes |= attributes;
isc_mutex_init(&disp->lock);
disp->failsafe_ev = allocate_devent(disp);
disp->magic = DISPATCH_MAGIC;
*dispp = disp;
return (ISC_R_SUCCESS);
}
/*
@ -1720,30 +1754,38 @@ dispatch_free(dns_dispatch_t **dispp) {
}
isc_result_t
dns_dispatch_createtcp(dns_dispatchmgr_t *mgr, isc_socket_t *sock,
dns_dispatch_createtcp(dns_dispatchmgr_t *mgr, isc_socketmgr_t *sockmgr,
isc_taskmgr_t *taskmgr, const isc_sockaddr_t *localaddr,
const isc_sockaddr_t *destaddr, unsigned int attributes,
dns_dispatch_t **dispp) {
isc_dscp_t dscp, dns_dispatch_t **dispp) {
isc_result_t result;
dns_dispatch_t *disp = NULL;
isc_sockaddr_t src;
int pf;
REQUIRE(VALID_DISPATCHMGR(mgr));
REQUIRE(isc_socket_gettype(sock) == isc_sockettype_tcp);
attributes |= DNS_DISPATCHATTR_TCP;
attributes &= ~DNS_DISPATCHATTR_UDP;
REQUIRE(sockmgr != NULL);
REQUIRE(destaddr != NULL);
LOCK(&mgr->lock);
result = dispatch_allocate(mgr, &disp);
if (result != ISC_R_SUCCESS) {
UNLOCK(&mgr->lock);
return (result);
}
pf = isc_sockaddr_pf(destaddr);
dispatch_allocate(mgr, isc_sockettype_tcp, pf, attributes, &disp);
disp->socktype = isc_sockettype_tcp;
isc_socket_attach(sock, &disp->socket);
disp->peer = *destaddr;
if (localaddr != NULL) {
disp->local = *localaddr;
} else {
switch (pf) {
case AF_INET:
isc_sockaddr_any(&disp->local);
break;
case AF_INET6:
isc_sockaddr_any6(&disp->local);
break;
}
}
disp->ntasks = 1;
disp->task[0] = NULL;
@ -1752,6 +1794,26 @@ dns_dispatch_createtcp(dns_dispatchmgr_t *mgr, isc_socket_t *sock,
goto cleanup;
}
result = isc_socket_create(sockmgr, isc_sockaddr_pf(destaddr),
isc_sockettype_tcp, &disp->socket);
if (result != ISC_R_SUCCESS) {
goto cleanup;
}
if (localaddr == NULL) {
isc_sockaddr_anyofpf(&src, pf);
} else {
src = *localaddr;
isc_sockaddr_setport(&src, 0);
}
result = isc_socket_bind(disp->socket, &src, 0);
if (result != ISC_R_SUCCESS) {
goto cleanup;
}
isc_socket_dscp(disp->socket, dscp);
disp->ctlevent =
isc_event_allocate(mgr->mctx, disp, DNS_EVENT_DISPATCHCONTROL,
destroy_disp, disp, sizeof(isc_event_t));
@ -1761,48 +1823,6 @@ dns_dispatch_createtcp(dns_dispatchmgr_t *mgr, isc_socket_t *sock,
dns_tcpmsg_init(mgr->mctx, disp->socket, &disp->tcpmsg);
disp->tcpmsg_valid = 1;
if (destaddr == NULL) {
(void)isc_socket_getpeername(sock, &disp->peer);
attributes |= DNS_DISPATCHATTR_PRIVATE;
} else {
disp->peer = *destaddr;
}
pf = isc_sockaddr_pf(&disp->peer);
if (localaddr == NULL) {
if (destaddr != NULL) {
switch (pf) {
case AF_INET:
isc_sockaddr_any(&disp->local);
break;
case AF_INET6:
isc_sockaddr_any6(&disp->local);
break;
}
} else {
(void)isc_socket_getsockname(sock, &disp->local);
}
} else {
disp->local = *localaddr;
}
switch (pf) {
case PF_INET:
attributes |= DNS_DISPATCHATTR_IPV4;
break;
case PF_INET6:
attributes |= DNS_DISPATCHATTR_IPV6;
break;
default:
result = ISC_R_NOTIMPLEMENTED;
goto cleanup;
}
disp->attributes = attributes;
/*
* Append it to the dispatcher list.
*/
@ -1908,6 +1928,7 @@ dns_dispatch_gettcp(dns_dispatchmgr_t *mgr, const isc_sockaddr_t *destaddr,
disp = ISC_LIST_NEXT(disp, link);
}
UNLOCK(&mgr->lock);
return (match ? ISC_R_SUCCESS : ISC_R_NOTFOUND);
}
@ -1924,43 +1945,29 @@ dns_dispatch_createudp(dns_dispatchmgr_t *mgr, isc_socketmgr_t *sockmgr,
REQUIRE(taskmgr != NULL);
REQUIRE(dispp != NULL && *dispp == NULL);
attributes |= DNS_DISPATCHATTR_UDP;
attributes &= ~DNS_DISPATCHATTR_TCP;
LOCK(&mgr->lock);
result = dispatch_createudp(mgr, sockmgr, taskmgr, localaddr,
attributes, &disp);
if (result == ISC_R_SUCCESS) {
*dispp = disp;
}
UNLOCK(&mgr->lock);
return (ISC_R_SUCCESS);
return (result);
}
static isc_result_t
dispatch_createudp(dns_dispatchmgr_t *mgr, isc_socketmgr_t *sockmgr,
isc_taskmgr_t *taskmgr, const isc_sockaddr_t *localaddr,
unsigned int attributes, dns_dispatch_t **dispp) {
isc_result_t result;
isc_result_t result = ISC_R_SUCCESS;
dns_dispatch_t *disp = NULL;
isc_socket_t *sock = NULL;
isc_sockaddr_t sa_any;
int pf, i = 0;
/*
* dispatch_allocate() checks mgr for us.
*/
disp = NULL;
result = dispatch_allocate(mgr, &disp);
if (result != ISC_R_SUCCESS) {
return (result);
}
pf = isc_sockaddr_pf(localaddr);
disp->socktype = isc_sockettype_udp;
dispatch_allocate(mgr, isc_sockettype_udp, pf, attributes, &disp);
/*
* For dispatches with a specified source address, we open a
@ -2014,25 +2021,6 @@ dispatch_createudp(dns_dispatchmgr_t *mgr, isc_socketmgr_t *sockmgr,
isc_mem_create(&disp->sepool);
isc_mem_setname(disp->sepool, "disp_sepool");
attributes &= ~DNS_DISPATCHATTR_TCP;
attributes |= DNS_DISPATCHATTR_UDP;
switch (pf) {
case PF_INET:
attributes |= DNS_DISPATCHATTR_IPV4;
break;
case PF_INET6:
attributes |= DNS_DISPATCHATTR_IPV6;
break;
default:
result = ISC_R_NOTIMPLEMENTED;
goto kill_socket;
}
disp->attributes = attributes;
/*
* Append it to the dispatcher list.
*/

4
lib/dns/include/dns/dispatch.h
View File

@ -223,10 +223,10 @@ dns_dispatch_createudp(dns_dispatchmgr_t *mgr, isc_socketmgr_t *sockmgr,
*/
isc_result_t
dns_dispatch_createtcp(dns_dispatchmgr_t *mgr, isc_socket_t *sock,
dns_dispatch_createtcp(dns_dispatchmgr_t *mgr, isc_socketmgr_t *sockmgr,
isc_taskmgr_t *taskmgr, const isc_sockaddr_t *localaddr,
const isc_sockaddr_t *destaddr, unsigned int attributes,
dns_dispatch_t **dispp);
isc_dscp_t dscp, dns_dispatch_t **dispp);
/*%<
* Create a new dns_dispatch and attach it to the provided isc_socket_t.
*

31
lib/dns/request.c
View File

@ -498,9 +498,6 @@ tcp_dispatch(bool newtcp, dns_requestmgr_t *requestmgr,
const isc_sockaddr_t *srcaddr, const isc_sockaddr_t *destaddr,
isc_dscp_t dscp, bool *connected, dns_dispatch_t **dispatchp) {
isc_result_t result;
isc_socket_t *sock = NULL;
isc_sockaddr_t src;
isc_sockaddr_t bind_any;
if (!newtcp) {
result = dns_dispatch_gettcp(requestmgr->dispatchmgr, destaddr,
@ -517,31 +514,9 @@ tcp_dispatch(bool newtcp, dns_requestmgr_t *requestmgr,
}
}
result = isc_socket_create(requestmgr->socketmgr,
isc_sockaddr_pf(destaddr),
isc_sockettype_tcp, &sock);
if (result != ISC_R_SUCCESS) {
return (result);
}
if (srcaddr == NULL) {
isc_sockaddr_anyofpf(&bind_any, isc_sockaddr_pf(destaddr));
result = isc_socket_bind(sock, &bind_any, 0);
} else {
src = *srcaddr;
isc_sockaddr_setport(&src, 0);
result = isc_socket_bind(sock, &src, 0);
}
if (result != ISC_R_SUCCESS) {
goto cleanup;
}
isc_socket_dscp(sock, dscp);
result = dns_dispatch_createtcp(requestmgr->dispatchmgr, sock,
requestmgr->taskmgr, srcaddr, destaddr,
0, dispatchp);
cleanup:
isc_socket_detach(&sock);
result = dns_dispatch_createtcp(
requestmgr->dispatchmgr, requestmgr->socketmgr,
requestmgr->taskmgr, srcaddr, destaddr, 0, dscp, dispatchp);
return (result);
}

128
lib/dns/resolver.c
View File

@ -228,7 +228,6 @@ typedef struct query {
dns_dispatchmgr_t *dispatchmgr;
dns_dispatch_t *dispatch;
dns_adbaddrinfo_t *addrinfo;
isc_socket_t *tcpsocket;
isc_time_t start;
dns_messageid_t id;
dns_dispentry_t *dispentry;
@ -1200,7 +1199,7 @@ resquery_destroy(resquery_t **queryp) {
*queryp = NULL;
REQUIRE(!ISC_LINK_LINKED(query, link));
INSIST(query->tcpsocket == NULL);
INSIST(query->dispatch == NULL);
fctx = query->fctx;
res = fctx->res;
@ -1245,13 +1244,13 @@ update_edns_stats(resquery_t *query) {
static void
fctx_cancelquery(resquery_t **queryp, dns_dispatchevent_t **deventp,
isc_time_t *finish, bool no_response, bool age_untried) {
fetchctx_t *fctx;
resquery_t *query;
fetchctx_t *fctx = NULL;
resquery_t *query = NULL;
unsigned int rtt, rttms;
unsigned int factor;
dns_adbfind_t *find;
dns_adbfind_t *find = NULL;
isc_socket_t *sock = NULL;
dns_adbaddrinfo_t *addrinfo;
isc_socket_t *sock;
isc_stdtime_t now;
query = *queryp;
@ -1423,33 +1422,20 @@ fctx_cancelquery(resquery_t **queryp, dns_dispatchevent_t **deventp,
* only needs to worry about managing the connect and send events;
* the dispatcher manages the recv events.
*/
if (RESQUERY_CONNECTING(query)) {
/*
* Cancel the connect.
*/
if (query->tcpsocket != NULL) {
isc_socket_cancel(query->tcpsocket, NULL,
ISC_SOCKCANCEL_CONNECT);
} else if (query->dispentry != NULL) {
sock = dns_dispatch_getentrysocket(query->dispentry);
if (sock != NULL) {
isc_socket_cancel(sock, NULL,
ISC_SOCKCANCEL_CONNECT);
}
}
if (query->dispentry != NULL) {
sock = dns_dispatch_getentrysocket(query->dispentry);
} else {
sock = dns_dispatch_getsocket(query->dispatch);
}
if (RESQUERY_SENDING(query)) {
/*
* Cancel the pending send.
*/
if (query->dispentry != NULL) {
sock = dns_dispatch_getentrysocket(query->dispentry);
} else {
sock = dns_dispatch_getsocket(query->dispatch);
}
if (sock != NULL) {
isc_socket_cancel(sock, NULL, ISC_SOCKCANCEL_SEND);
}
/* Cancel the connect. */
if (sock != NULL && RESQUERY_CONNECTING(query)) {
isc_socket_cancel(sock, NULL, ISC_SOCKCANCEL_CONNECT);
}
/* Cancel the pending send. */
if (sock != NULL && RESQUERY_SENDING(query)) {
isc_socket_cancel(sock, NULL, ISC_SOCKCANCEL_SEND);
}
if (query->dispentry != NULL) {
@ -1829,19 +1815,12 @@ process_sendevent(resquery_t *query, isc_event_t *event) {
bool destroy_query = false;
bool retry = false;
isc_result_t result;
fetchctx_t *fctx;
fetchctx_t *fctx = NULL;
fctx = query->fctx;
if (RESQUERY_CANCELED(query)) {
if (query->sends == 0 && query->connects == 0) {
/*
* This query was canceled while the
* isc_socket_sendto/connect() was in progress.
*/
if (query->tcpsocket != NULL) {
isc_socket_detach(&query->tcpsocket);
}
destroy_query = true;
}
} else {
@ -2007,10 +1986,10 @@ fctx_setretryinterval(fetchctx_t *fctx, unsigned int rtt) {
static isc_result_t
fctx_query(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
unsigned int options) {
dns_resolver_t *res;
isc_task_t *task;
dns_resolver_t *res = NULL;
isc_task_t *task = NULL;
isc_result_t result;
resquery_t *query;
resquery_t *query = NULL;
isc_sockaddr_t addr;
bool have_addr = false;
unsigned int srtt;
@ -2123,21 +2102,12 @@ fctx_query(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
query->dscp = dscp;
}
result = isc_socket_create(res->socketmgr, pf,
isc_sockettype_tcp,
&query->tcpsocket);
result = dns_dispatch_createtcp(
res->dispatchmgr, res->socketmgr, res->taskmgr, &addr,
&addrinfo->sockaddr, 0, query->dscp, &query->dispatch);
if (result != ISC_R_SUCCESS) {
goto cleanup_query;
}
result = isc_socket_bind(query->tcpsocket, &addr, 0);
if (result != ISC_R_SUCCESS) {
goto cleanup_socket;
}
/*
* A dispatch will be created once the connect succeeds.
*/
} else {
if (have_addr) {
switch (isc_sockaddr_pf(&addr)) {
@ -2195,19 +2165,16 @@ fctx_query(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
query->magic = QUERY_MAGIC;
if ((query->options & DNS_FETCHOPT_TCP) != 0) {
isc_socket_t *sock = NULL;
/*
* Connect to the remote server.
*
* XXXRTH Should we attach to the socket?
*/
if (query->dscp != -1) {
isc_socket_dscp(query->tcpsocket, query->dscp);
}
result = isc_socket_connect(query->tcpsocket,
&addrinfo->sockaddr, task,
sock = dns_dispatch_getsocket(query->dispatch);
result = isc_socket_connect(sock, &addrinfo->sockaddr, task,
resquery_connected, query);
if (result != ISC_R_SUCCESS) {
goto cleanup_socket;
goto cleanup_dispatch;
}
query->connects++;
QTRACE("connecting via TCP");
@ -2244,9 +2211,6 @@ fctx_query(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
return (ISC_R_SUCCESS);
cleanup_socket:
isc_socket_detach(&query->tcpsocket);
cleanup_dispatch:
if (query->dispatch != NULL) {
dns_dispatch_detach(&query->dispatch);
@ -2961,11 +2925,8 @@ resquery_connected(isc_task_t *task, isc_event_t *event) {
* This query was canceled while the connect() was in
* progress.
*/
isc_socket_detach(&query->tcpsocket);
resquery_destroy(&query);
} else {
int attrs = 0;
switch (sevent->result) {
case ISC_R_SUCCESS:
@ -2989,27 +2950,16 @@ resquery_connected(isc_task_t *task, isc_event_t *event) {
fctx_done(fctx, result, __LINE__);
break;
}
/*
* We are connected. Create a dispatcher and
* We are connected. Update the dispatcher and
* send the query.
*/
attrs = DNS_DISPATCHATTR_CONNECTED;
result = dns_dispatch_createtcp(
query->dispatchmgr, query->tcpsocket,
query->fctx->res->taskmgr, NULL, NULL, attrs,
&query->dispatch);
/*
* Regardless of whether dns_dispatch_create()
* succeeded or not, we don't need our reference
* to the socket anymore.
*/
isc_socket_detach(&query->tcpsocket);
if (result == ISC_R_SUCCESS) {
result = resquery_send(query);
}
dns_dispatch_changeattributes(
query->dispatch, DNS_DISPATCHATTR_CONNECTED,
DNS_DISPATCHATTR_CONNECTED);
result = resquery_send(query);
if (result != ISC_R_SUCCESS) {
FCTXTRACE("query canceled: "
"resquery_send() failed; responding");
@ -3030,10 +2980,6 @@ resquery_connected(isc_task_t *task, isc_event_t *event) {
"no route to host; no response",
sevent->result);
/*
* No route to remote.
*/
isc_socket_detach(&query->tcpsocket);
/*
* Do not query this server again in this fetch context
* if the server is unavailable over TCP.
@ -3049,7 +2995,7 @@ resquery_connected(isc_task_t *task, isc_event_t *event) {
"unexpected event result; responding",
sevent->result);
isc_socket_detach(&query->tcpsocket);
dns_dispatch_detach(&query->dispatch);
fctx_cancelquery(&query, NULL, NULL, false, false);
break;
}