Mercurial > hg > nginx
view src/http/v2/ngx_http_v2_table.c @ 6891:749bcfdf097a stable-1.10
HTTP/2: fixed posted streams handling.
A bug was introduced by 82efcedb310b that could lead to timing out of
responses or segmentation fault, when accept_mutex was enabled.
The output queue in HTTP/2 can contain frames from different streams.
When the queue is sent, all related write handlers need to be called.
In order to do so, the streams were added to the h2c->posted queue
after handling sent frames. Then this queue was processed in
ngx_http_v2_write_handler().
If accept_mutex is enabled, the event's "ready" flag is set but its
handler is not called immediately. Instead, the event is added to
the ngx_posted_events queue. At the same time in this queue can be
events from upstream connections. Such events can result in sending
output queue before ngx_http_v2_write_handler() is triggered. And
at the time ngx_http_v2_write_handler() is called, the output queue
can be already empty with some streams added to h2c->posted.
But after 82efcedb310b, these streams weren't processed if all frames
have already been sent and the output queue was empty. This might lead
to a situation when a number of streams were get stuck in h2c->posted
queue for a long time. Eventually these streams might get closed by
the send timeout.
In the worst case this might also lead to a segmentation fault, if
already freed stream was left in the h2c->posted queue. This could
happen if one of the streams was terminated but wasn't closed, due to
the HEADERS frame or a partially sent DATA frame left in the output
queue. If this happened the ngx_http_v2_filter_cleanup() handler
removed the stream from the h2c->waiting or h2c->posted queue on
termination stage, before the frame has been sent, and the stream
was again added to the h2c->posted queue after the frame was sent.
In order to fix all these problems and simplify the code, write
events of fake stream connections are now added to ngx_posted_events
instead of using a custom h2c->posted queue.
author | Valentin Bartenev <vbart@nginx.com> |
---|---|
date | Mon, 28 Nov 2016 20:58:14 +0300 |
parents | 257b51c37c5a |
children | d4b031cf32cf |
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/* * Copyright (C) Nginx, Inc. * Copyright (C) Valentin V. Bartenev */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> #define NGX_HTTP_V2_TABLE_SIZE 4096 static ngx_int_t ngx_http_v2_table_account(ngx_http_v2_connection_t *h2c, size_t size); static ngx_http_v2_header_t ngx_http_v2_static_table[] = { { ngx_string(":authority"), ngx_string("") }, { ngx_string(":method"), ngx_string("GET") }, { ngx_string(":method"), ngx_string("POST") }, { ngx_string(":path"), ngx_string("/") }, { ngx_string(":path"), ngx_string("/index.html") }, { ngx_string(":scheme"), ngx_string("http") }, { ngx_string(":scheme"), ngx_string("https") }, { ngx_string(":status"), ngx_string("200") }, { ngx_string(":status"), ngx_string("204") }, { ngx_string(":status"), ngx_string("206") }, { ngx_string(":status"), ngx_string("304") }, { ngx_string(":status"), ngx_string("400") }, { ngx_string(":status"), ngx_string("404") }, { ngx_string(":status"), ngx_string("500") }, { ngx_string("accept-charset"), ngx_string("") }, { ngx_string("accept-encoding"), ngx_string("gzip, deflate") }, { ngx_string("accept-language"), ngx_string("") }, { ngx_string("accept-ranges"), ngx_string("") }, { ngx_string("accept"), ngx_string("") }, { ngx_string("access-control-allow-origin"), ngx_string("") }, { ngx_string("age"), ngx_string("") }, { ngx_string("allow"), ngx_string("") }, { ngx_string("authorization"), ngx_string("") }, { ngx_string("cache-control"), ngx_string("") }, { ngx_string("content-disposition"), ngx_string("") }, { ngx_string("content-encoding"), ngx_string("") }, { ngx_string("content-language"), ngx_string("") }, { ngx_string("content-length"), ngx_string("") }, { ngx_string("content-location"), ngx_string("") }, { ngx_string("content-range"), ngx_string("") }, { ngx_string("content-type"), ngx_string("") }, { ngx_string("cookie"), ngx_string("") }, { ngx_string("date"), ngx_string("") }, { ngx_string("etag"), ngx_string("") }, { ngx_string("expect"), ngx_string("") }, { ngx_string("expires"), ngx_string("") }, { ngx_string("from"), ngx_string("") }, { ngx_string("host"), ngx_string("") }, { ngx_string("if-match"), ngx_string("") }, { ngx_string("if-modified-since"), ngx_string("") }, { ngx_string("if-none-match"), ngx_string("") }, { ngx_string("if-range"), ngx_string("") }, { ngx_string("if-unmodified-since"), ngx_string("") }, { ngx_string("last-modified"), ngx_string("") }, { ngx_string("link"), ngx_string("") }, { ngx_string("location"), ngx_string("") }, { ngx_string("max-forwards"), ngx_string("") }, { ngx_string("proxy-authenticate"), ngx_string("") }, { ngx_string("proxy-authorization"), ngx_string("") }, { ngx_string("range"), ngx_string("") }, { ngx_string("referer"), ngx_string("") }, { ngx_string("refresh"), ngx_string("") }, { ngx_string("retry-after"), ngx_string("") }, { ngx_string("server"), ngx_string("") }, { ngx_string("set-cookie"), ngx_string("") }, { ngx_string("strict-transport-security"), ngx_string("") }, { ngx_string("transfer-encoding"), ngx_string("") }, { ngx_string("user-agent"), ngx_string("") }, { ngx_string("vary"), ngx_string("") }, { ngx_string("via"), ngx_string("") }, { ngx_string("www-authenticate"), ngx_string("") }, }; #define NGX_HTTP_V2_STATIC_TABLE_ENTRIES \ (sizeof(ngx_http_v2_static_table) \ / sizeof(ngx_http_v2_header_t)) ngx_int_t ngx_http_v2_get_indexed_header(ngx_http_v2_connection_t *h2c, ngx_uint_t index, ngx_uint_t name_only) { u_char *p; size_t rest; ngx_http_v2_header_t *entry; if (index == 0) { ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0, "client sent invalid hpack table index 0"); return NGX_ERROR; } ngx_log_debug2(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, "http2 get indexed %s: %ui", name_only ? "header" : "header name", index); index--; if (index < NGX_HTTP_V2_STATIC_TABLE_ENTRIES) { h2c->state.header = ngx_http_v2_static_table[index]; return NGX_OK; } index -= NGX_HTTP_V2_STATIC_TABLE_ENTRIES; if (index < h2c->hpack.added - h2c->hpack.deleted) { index = (h2c->hpack.added - index - 1) % h2c->hpack.allocated; entry = h2c->hpack.entries[index]; p = ngx_pnalloc(h2c->state.pool, entry->name.len + 1); if (p == NULL) { return NGX_ERROR; } h2c->state.header.name.len = entry->name.len; h2c->state.header.name.data = p; rest = h2c->hpack.storage + NGX_HTTP_V2_TABLE_SIZE - entry->name.data; if (entry->name.len > rest) { p = ngx_cpymem(p, entry->name.data, rest); p = ngx_cpymem(p, h2c->hpack.storage, entry->name.len - rest); } else { p = ngx_cpymem(p, entry->name.data, entry->name.len); } *p = '\0'; if (name_only) { return NGX_OK; } p = ngx_pnalloc(h2c->state.pool, entry->value.len + 1); if (p == NULL) { return NGX_ERROR; } h2c->state.header.value.len = entry->value.len; h2c->state.header.value.data = p; rest = h2c->hpack.storage + NGX_HTTP_V2_TABLE_SIZE - entry->value.data; if (entry->value.len > rest) { p = ngx_cpymem(p, entry->value.data, rest); p = ngx_cpymem(p, h2c->hpack.storage, entry->value.len - rest); } else { p = ngx_cpymem(p, entry->value.data, entry->value.len); } *p = '\0'; return NGX_OK; } ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0, "client sent out of bound hpack table index: %ui", index); return NGX_ERROR; } ngx_int_t ngx_http_v2_add_header(ngx_http_v2_connection_t *h2c, ngx_http_v2_header_t *header) { size_t avail; ngx_uint_t index; ngx_http_v2_header_t *entry, **entries; ngx_log_debug2(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, "http2 add header to hpack table: \"%V: %V\"", &header->name, &header->value); if (h2c->hpack.entries == NULL) { h2c->hpack.allocated = 64; h2c->hpack.size = NGX_HTTP_V2_TABLE_SIZE; h2c->hpack.free = NGX_HTTP_V2_TABLE_SIZE; h2c->hpack.entries = ngx_palloc(h2c->connection->pool, sizeof(ngx_http_v2_header_t *) * h2c->hpack.allocated); if (h2c->hpack.entries == NULL) { return NGX_ERROR; } h2c->hpack.storage = ngx_palloc(h2c->connection->pool, h2c->hpack.free); if (h2c->hpack.storage == NULL) { return NGX_ERROR; } h2c->hpack.pos = h2c->hpack.storage; } if (ngx_http_v2_table_account(h2c, header->name.len + header->value.len) != NGX_OK) { return NGX_OK; } if (h2c->hpack.reused == h2c->hpack.deleted) { entry = ngx_palloc(h2c->connection->pool, sizeof(ngx_http_v2_header_t)); if (entry == NULL) { return NGX_ERROR; } } else { entry = h2c->hpack.entries[h2c->hpack.reused++ % h2c->hpack.allocated]; } avail = h2c->hpack.storage + NGX_HTTP_V2_TABLE_SIZE - h2c->hpack.pos; entry->name.len = header->name.len; entry->name.data = h2c->hpack.pos; if (avail >= header->name.len) { h2c->hpack.pos = ngx_cpymem(h2c->hpack.pos, header->name.data, header->name.len); } else { ngx_memcpy(h2c->hpack.pos, header->name.data, avail); h2c->hpack.pos = ngx_cpymem(h2c->hpack.storage, header->name.data + avail, header->name.len - avail); avail = NGX_HTTP_V2_TABLE_SIZE; } avail -= header->name.len; entry->value.len = header->value.len; entry->value.data = h2c->hpack.pos; if (avail >= header->value.len) { h2c->hpack.pos = ngx_cpymem(h2c->hpack.pos, header->value.data, header->value.len); } else { ngx_memcpy(h2c->hpack.pos, header->value.data, avail); h2c->hpack.pos = ngx_cpymem(h2c->hpack.storage, header->value.data + avail, header->value.len - avail); } if (h2c->hpack.allocated == h2c->hpack.added - h2c->hpack.deleted) { entries = ngx_palloc(h2c->connection->pool, sizeof(ngx_http_v2_header_t *) * (h2c->hpack.allocated + 64)); if (entries == NULL) { return NGX_ERROR; } index = h2c->hpack.deleted % h2c->hpack.allocated; ngx_memcpy(entries, &h2c->hpack.entries[index], (h2c->hpack.allocated - index) * sizeof(ngx_http_v2_header_t *)); ngx_memcpy(&entries[h2c->hpack.allocated - index], h2c->hpack.entries, index * sizeof(ngx_http_v2_header_t *)); (void) ngx_pfree(h2c->connection->pool, h2c->hpack.entries); h2c->hpack.entries = entries; h2c->hpack.added = h2c->hpack.allocated; h2c->hpack.deleted = 0; h2c->hpack.reused = 0; h2c->hpack.allocated += 64; } h2c->hpack.entries[h2c->hpack.added++ % h2c->hpack.allocated] = entry; return NGX_OK; } static ngx_int_t ngx_http_v2_table_account(ngx_http_v2_connection_t *h2c, size_t size) { ngx_http_v2_header_t *entry; size += 32; ngx_log_debug2(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, "http2 hpack table account: %uz free:%uz", size, h2c->hpack.free); if (size <= h2c->hpack.free) { h2c->hpack.free -= size; return NGX_OK; } if (size > h2c->hpack.size) { h2c->hpack.deleted = h2c->hpack.added; h2c->hpack.free = h2c->hpack.size; return NGX_DECLINED; } do { entry = h2c->hpack.entries[h2c->hpack.deleted++ % h2c->hpack.allocated]; h2c->hpack.free += 32 + entry->name.len + entry->value.len; } while (size > h2c->hpack.free); h2c->hpack.free -= size; return NGX_OK; } ngx_int_t ngx_http_v2_table_size(ngx_http_v2_connection_t *h2c, size_t size) { ssize_t needed; ngx_http_v2_header_t *entry; if (size > NGX_HTTP_V2_TABLE_SIZE) { ngx_log_error(NGX_LOG_INFO, h2c->connection->log, 0, "client sent invalid table size update: %uz", size); return NGX_ERROR; } ngx_log_debug2(NGX_LOG_DEBUG_HTTP, h2c->connection->log, 0, "http2 new hpack table size: %uz was:%uz", size, h2c->hpack.size); needed = h2c->hpack.size - size; while (needed > (ssize_t) h2c->hpack.free) { entry = h2c->hpack.entries[h2c->hpack.deleted++ % h2c->hpack.allocated]; h2c->hpack.free += 32 + entry->name.len + entry->value.len; } h2c->hpack.size = size; h2c->hpack.free -= needed; return NGX_OK; }