view src/event/quic/ngx_event_quic_socket.c @ 8971:1e2f4e9c8195 quic

QUIC: reworked migration handling. The quic connection now holds active, backup and probe paths instead of sockets. The number of migration paths is now limited and cannot be inflated by a bad client or an attacker. The client id is now associated with path rather than socket. This allows to simplify processing of output and connection ids handling. New migration abandons any previously started migrations. This allows to free consumed client ids and request new for use in future migrations and make progress in case when connection id limit is hit during migration. A path now can be revalidated without losing its state. The patch also fixes various issues with NAT rebinding case handling: - paths are now validated (previously, there was no validation and paths were left in limited state) - attempt to reuse id on different path is now again verified (this was broken in 40445fc7c403) - former path is now validated in case of apparent migration
author Vladimir Homutov <vl@nginx.com>
date Wed, 19 Jan 2022 22:39:24 +0300
parents 32daba3aabb2
children fab36e4abf83
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/*
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>
#include <ngx_event_quic_connection.h>


ngx_int_t
ngx_quic_open_sockets(ngx_connection_t *c, ngx_quic_connection_t *qc,
    ngx_quic_header_t *pkt)
{
    ngx_quic_socket_t     *qsock, *tmp;
    ngx_quic_client_id_t  *cid;

    /*
     * qc->path = NULL
     *
     * qc->nclient_ids = 0
     * qc->nsockets = 0
     * qc->max_retired_seqnum = 0
     * qc->client_seqnum = 0
     */

    ngx_queue_init(&qc->sockets);
    ngx_queue_init(&qc->free_sockets);

    ngx_queue_init(&qc->paths);
    ngx_queue_init(&qc->free_paths);

    ngx_queue_init(&qc->client_ids);
    ngx_queue_init(&qc->free_client_ids);

    qc->tp.original_dcid.len = pkt->odcid.len;
    qc->tp.original_dcid.data = ngx_pstrdup(c->pool, &pkt->odcid);
    if (qc->tp.original_dcid.data == NULL) {
         return NGX_ERROR;
    }

    /* socket to use for further processing (id auto-generated) */
    qsock = ngx_quic_create_socket(c, qc);
    if (qsock == NULL) {
        return NGX_ERROR;
    }

    /* socket is listening at new server id */
    if (ngx_quic_listen(c, qc, qsock) != NGX_OK) {
        return NGX_ERROR;
    }

    qsock->used = 1;

    qc->tp.initial_scid.len = qsock->sid.len;
    qc->tp.initial_scid.data = ngx_pnalloc(c->pool, qsock->sid.len);
    if (qc->tp.initial_scid.data == NULL) {
        goto failed;
    }
    ngx_memcpy(qc->tp.initial_scid.data, qsock->sid.id, qsock->sid.len);

    /* for all packets except first, this is set at udp layer */
    c->udp = &qsock->udp;

    /* ngx_quic_get_connection(c) macro is now usable */

    /* we have a client identified by scid */
    cid = ngx_quic_create_client_id(c, &pkt->scid, 0, NULL);
    if (cid == NULL) {
        goto failed;
    }

    /* path of the first packet is our initial active path */
    qc->path = ngx_quic_new_path(c, c->sockaddr, c->socklen, cid);
    if (qc->path == NULL) {
        goto failed;
    }

    qc->path->tag = NGX_QUIC_PATH_ACTIVE;

    if (pkt->validated) {
        qc->path->validated = 1;
        qc->path->limited = 0;
    }

    ngx_quic_path_dbg(c, "set active", qc->path);

    tmp = ngx_pcalloc(c->pool, sizeof(ngx_quic_socket_t));
    if (tmp == NULL) {
        goto failed;
    }

    tmp->sid.seqnum = NGX_QUIC_UNSET_PN; /* temporary socket */

    ngx_memcpy(tmp->sid.id, pkt->odcid.data, pkt->odcid.len);
    tmp->sid.len = pkt->odcid.len;

    if (ngx_quic_listen(c, qc, tmp) != NGX_OK) {
        goto failed;
    }

    return NGX_OK;

failed:

    ngx_rbtree_delete(&c->listening->rbtree, &qsock->udp.node);
    c->udp = NULL;

    return NGX_ERROR;
}


ngx_quic_socket_t *
ngx_quic_create_socket(ngx_connection_t *c, ngx_quic_connection_t *qc)
{
    ngx_queue_t        *q;
    ngx_quic_socket_t  *sock;

    if (!ngx_queue_empty(&qc->free_sockets)) {

        q = ngx_queue_head(&qc->free_sockets);
        sock = ngx_queue_data(q, ngx_quic_socket_t, queue);

        ngx_queue_remove(&sock->queue);

        ngx_memzero(sock, sizeof(ngx_quic_socket_t));

    } else {

        sock = ngx_pcalloc(c->pool, sizeof(ngx_quic_socket_t));
        if (sock == NULL) {
            return NULL;
        }
    }

    sock->sid.len = NGX_QUIC_SERVER_CID_LEN;
    if (ngx_quic_create_server_id(c, sock->sid.id) != NGX_OK) {
        return NULL;
    }

    sock->sid.seqnum = qc->server_seqnum++;

    return sock;
}


void
ngx_quic_close_socket(ngx_connection_t *c, ngx_quic_socket_t *qsock)
{
    ngx_quic_connection_t  *qc;

    qc = ngx_quic_get_connection(c);

    ngx_queue_remove(&qsock->queue);
    ngx_queue_insert_head(&qc->free_sockets, &qsock->queue);

    ngx_rbtree_delete(&c->listening->rbtree, &qsock->udp.node);
    qc->nsockets--;

    ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0,
                   "quic socket #%L closed nsock:%ui",
                   (int64_t) qsock->sid.seqnum, qc->nsockets);
}


ngx_int_t
ngx_quic_listen(ngx_connection_t *c, ngx_quic_connection_t *qc,
    ngx_quic_socket_t *qsock)
{
    ngx_str_t              id;
    ngx_quic_server_id_t  *sid;

    sid = &qsock->sid;

    id.data = sid->id;
    id.len = sid->len;

    ngx_insert_udp_connection(c, &qsock->udp, &id);

    ngx_queue_insert_tail(&qc->sockets, &qsock->queue);

    qc->nsockets++;
    qsock->quic = qc;

    ngx_log_debug3(NGX_LOG_DEBUG_EVENT, c->log, 0,
                   "quic socket #%L listening at sid:%xV nsock:%ui",
                   (int64_t) sid->seqnum, &id, qc->nsockets);

    return NGX_OK;
}


void
ngx_quic_close_sockets(ngx_connection_t *c)
{
    ngx_queue_t            *q;
    ngx_quic_socket_t      *qsock;
    ngx_quic_connection_t  *qc;

    qc = ngx_quic_get_connection(c);

    while (!ngx_queue_empty(&qc->sockets)) {
        q = ngx_queue_head(&qc->sockets);
        qsock = ngx_queue_data(q, ngx_quic_socket_t, queue);

        ngx_quic_close_socket(c, qsock);
    }
}


ngx_quic_socket_t *
ngx_quic_find_socket(ngx_connection_t *c, uint64_t seqnum)
{
    ngx_queue_t            *q;
    ngx_quic_socket_t      *qsock;
    ngx_quic_connection_t  *qc;

    qc = ngx_quic_get_connection(c);

    for (q = ngx_queue_head(&qc->sockets);
         q != ngx_queue_sentinel(&qc->sockets);
         q = ngx_queue_next(q))
    {
        qsock = ngx_queue_data(q, ngx_quic_socket_t, queue);

        if (qsock->sid.seqnum == seqnum) {
            return qsock;
        }
    }

    return NULL;
}