Mercurial > hg > nginx
view src/event/quic/ngx_event_quic_frames.c @ 8946:56dec0d4e5b1 quic
QUIC: avoid excessive buffer allocations in stream output.
Previously, when a few bytes were send to a QUIC stream by the application, a
4K buffer was allocated for these bytes. Then a STREAM frame was created and
that entire buffer was used as data for that frame. The frame with the buffer
were in use up until the frame was acked by client. Meanwhile, when more
bytes were send to the stream, more buffers were allocated and assigned as
data to newer STREAM frames. In this scenario most buffer memory is unused.
Now the unused part of the stream output buffer is available for further
stream output while earlier parts of the buffer are waiting to be acked.
This is achieved by splitting the output buffer.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Fri, 24 Dec 2021 18:13:51 +0300 |
parents | a6a328ebd362 |
children | 6ccf3867959a |
line wrap: on
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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> #define NGX_QUIC_BUFFER_SIZE 4096 static ngx_chain_t *ngx_quic_split_bufs(ngx_connection_t *c, ngx_chain_t *in, size_t len); ngx_quic_frame_t * ngx_quic_alloc_frame(ngx_connection_t *c) { ngx_queue_t *q; ngx_quic_frame_t *frame; ngx_quic_connection_t *qc; qc = ngx_quic_get_connection(c); if (!ngx_queue_empty(&qc->free_frames)) { q = ngx_queue_head(&qc->free_frames); frame = ngx_queue_data(q, ngx_quic_frame_t, queue); ngx_queue_remove(&frame->queue); #ifdef NGX_QUIC_DEBUG_ALLOC ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "quic reuse frame n:%ui", qc->nframes); #endif } else if (qc->nframes < 10000) { frame = ngx_palloc(c->pool, sizeof(ngx_quic_frame_t)); if (frame == NULL) { return NULL; } ++qc->nframes; #ifdef NGX_QUIC_DEBUG_ALLOC ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "quic alloc frame n:%ui", qc->nframes); #endif } else { ngx_log_error(NGX_LOG_INFO, c->log, 0, "quic flood detected"); return NULL; } ngx_memzero(frame, sizeof(ngx_quic_frame_t)); return frame; } void ngx_quic_free_frame(ngx_connection_t *c, ngx_quic_frame_t *frame) { ngx_quic_connection_t *qc; qc = ngx_quic_get_connection(c); if (frame->data) { ngx_quic_free_bufs(c, frame->data); } ngx_queue_insert_head(&qc->free_frames, &frame->queue); #ifdef NGX_QUIC_DEBUG_ALLOC ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "quic free frame n:%ui", qc->nframes); #endif } void ngx_quic_trim_bufs(ngx_chain_t *in, size_t size) { size_t n; ngx_buf_t *b; while (in && size > 0) { b = in->buf; n = ngx_min((size_t) (b->last - b->pos), size); b->pos += n; size -= n; if (b->pos == b->last) { in = in->next; } } } void ngx_quic_free_bufs(ngx_connection_t *c, ngx_chain_t *in) { ngx_buf_t *b, *shadow; ngx_chain_t *cl; ngx_quic_connection_t *qc; qc = ngx_quic_get_connection(c); while (in) { #ifdef NGX_QUIC_DEBUG_ALLOC ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "quic free buffer n:%ui", qc->nbufs); #endif cl = in; in = in->next; b = cl->buf; if (b->shadow) { if (!b->last_shadow) { b->recycled = 1; ngx_free_chain(c->pool, cl); continue; } do { shadow = b->shadow; b->shadow = qc->free_shadow_bufs; qc->free_shadow_bufs = b; b = shadow; } while (b->recycled); if (b->shadow) { b->last_shadow = 1; ngx_free_chain(c->pool, cl); continue; } cl->buf = b; } cl->next = qc->free_bufs; qc->free_bufs = cl; } } void ngx_quic_free_frames(ngx_connection_t *c, ngx_queue_t *frames) { ngx_queue_t *q; ngx_quic_frame_t *f; do { q = ngx_queue_head(frames); if (q == ngx_queue_sentinel(frames)) { break; } ngx_queue_remove(q); f = ngx_queue_data(q, ngx_quic_frame_t, queue); ngx_quic_free_frame(c, f); } while (1); } void ngx_quic_queue_frame(ngx_quic_connection_t *qc, ngx_quic_frame_t *frame) { ngx_quic_send_ctx_t *ctx; ctx = ngx_quic_get_send_ctx(qc, frame->level); ngx_queue_insert_tail(&ctx->frames, &frame->queue); frame->len = ngx_quic_create_frame(NULL, frame); /* always succeeds */ if (qc->closing) { return; } ngx_post_event(&qc->push, &ngx_posted_events); } ngx_int_t ngx_quic_split_frame(ngx_connection_t *c, ngx_quic_frame_t *f, size_t len) { size_t shrink; ngx_quic_frame_t *nf; ngx_quic_ordered_frame_t *of, *onf; switch (f->type) { case NGX_QUIC_FT_CRYPTO: case NGX_QUIC_FT_STREAM: break; default: return NGX_DECLINED; } if ((size_t) f->len <= len) { return NGX_OK; } shrink = f->len - len; ngx_log_debug3(NGX_LOG_DEBUG_EVENT, c->log, 0, "quic split frame now:%uz need:%uz shrink:%uz", f->len, len, shrink); of = &f->u.ord; if (of->length <= shrink) { return NGX_DECLINED; } of->length -= shrink; f->len = ngx_quic_create_frame(NULL, f); if ((size_t) f->len > len) { ngx_log_error(NGX_LOG_ERR, c->log, 0, "could not split QUIC frame"); return NGX_ERROR; } nf = ngx_quic_alloc_frame(c); if (nf == NULL) { return NGX_ERROR; } *nf = *f; onf = &nf->u.ord; onf->offset += of->length; onf->length = shrink; nf->len = ngx_quic_create_frame(NULL, nf); nf->data = ngx_quic_split_bufs(c, f->data, of->length); if (nf->data == NGX_CHAIN_ERROR) { return NGX_ERROR; } ngx_queue_insert_after(&f->queue, &nf->queue); return NGX_OK; } static ngx_chain_t * ngx_quic_split_bufs(ngx_connection_t *c, ngx_chain_t *in, size_t len) { size_t n; ngx_buf_t *b; ngx_chain_t *out; ngx_quic_connection_t *qc; qc = ngx_quic_get_connection(c); while (in) { n = ngx_buf_size(in->buf); if (n == len) { out = in->next; in->next = NULL; return out; } if (n > len) { break; } len -= n; in = in->next; } if (in == NULL) { return NULL; } /* split in->buf by creating shadow bufs which reference it */ if (in->buf->shadow == NULL) { if (qc->free_shadow_bufs) { b = qc->free_shadow_bufs; qc->free_shadow_bufs = b->shadow; } else { b = ngx_alloc_buf(c->pool); if (b == NULL) { return NGX_CHAIN_ERROR; } } *b = *in->buf; b->shadow = in->buf; b->last_shadow = 1; in->buf = b; } out = ngx_alloc_chain_link(c->pool); if (out == NULL) { return NGX_CHAIN_ERROR; } if (qc->free_shadow_bufs) { b = qc->free_shadow_bufs; qc->free_shadow_bufs = b->shadow; } else { b = ngx_alloc_buf(c->pool); if (b == NULL) { ngx_free_chain(c->pool, out); return NGX_CHAIN_ERROR; } } out->buf = b; out->next = in->next; in->next = NULL; *b = *in->buf; b->last_shadow = 0; b->pos = b->pos + len; in->buf->shadow = b; in->buf->last = in->buf->pos + len; return out; } ngx_chain_t * ngx_quic_alloc_buf(ngx_connection_t *c) { ngx_buf_t *b; ngx_chain_t *cl; ngx_quic_connection_t *qc; qc = ngx_quic_get_connection(c); if (qc->free_bufs) { cl = qc->free_bufs; qc->free_bufs = cl->next; b = cl->buf; b->pos = b->start; b->last = b->start; #ifdef NGX_QUIC_DEBUG_ALLOC ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "quic reuse buffer n:%ui", qc->nbufs); #endif return cl; } cl = ngx_alloc_chain_link(c->pool); if (cl == NULL) { return NULL; } b = ngx_create_temp_buf(c->pool, NGX_QUIC_BUFFER_SIZE); if (b == NULL) { return NULL; } b->tag = (ngx_buf_tag_t) &ngx_quic_alloc_buf; cl->buf = b; #ifdef NGX_QUIC_DEBUG_ALLOC ++qc->nbufs; ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "quic alloc buffer n:%ui", qc->nbufs); #endif return cl; } ngx_chain_t * ngx_quic_copy_buf(ngx_connection_t *c, u_char *data, size_t len) { size_t n; ngx_buf_t *b; ngx_chain_t *cl, *out, **ll; out = NULL; ll = &out; while (len) { cl = ngx_quic_alloc_buf(c); if (cl == NULL) { return NGX_CHAIN_ERROR; } b = cl->buf; n = ngx_min((size_t) (b->end - b->last), len); b->last = ngx_cpymem(b->last, data, n); data += n; len -= n; *ll = cl; ll = &cl->next; } *ll = NULL; return out; } ngx_chain_t * ngx_quic_copy_chain(ngx_connection_t *c, ngx_chain_t *in, size_t limit) { size_t n; ngx_buf_t *b; ngx_chain_t *cl, *out, **ll; out = NULL; ll = &out; while (in) { if (!ngx_buf_in_memory(in->buf) || ngx_buf_size(in->buf) == 0) { in = in->next; continue; } cl = ngx_quic_alloc_buf(c); if (cl == NULL) { return NGX_CHAIN_ERROR; } *ll = cl; ll = &cl->next; b = cl->buf; while (in && b->last != b->end) { n = ngx_min(in->buf->last - in->buf->pos, b->end - b->last); if (limit > 0 && n > limit) { n = limit; } b->last = ngx_cpymem(b->last, in->buf->pos, n); in->buf->pos += n; if (in->buf->pos == in->buf->last) { in = in->next; } if (limit > 0) { if (limit == n) { goto done; } limit -= n; } } } done: *ll = NULL; return out; } ngx_int_t ngx_quic_order_bufs(ngx_connection_t *c, ngx_chain_t **out, ngx_chain_t *in, off_t limit, off_t offset) { off_t n; u_char *p; ngx_buf_t *b; ngx_chain_t *cl, *sl; while (in && limit) { cl = *out; if (cl == NULL) { cl = ngx_quic_alloc_buf(c); if (cl == NULL) { return NGX_ERROR; } cl->buf->last = cl->buf->end; cl->buf->sync = 1; /* hole */ cl->next = NULL; *out = cl; } b = cl->buf; n = b->last - b->pos; if (n <= offset) { offset -= n; out = &cl->next; continue; } if (b->sync && offset > 0) { sl = ngx_quic_split_bufs(c, cl, offset); if (sl == NGX_CHAIN_ERROR) { return NGX_ERROR; } cl->next = sl; continue; } for (p = b->pos + offset; p != b->last && in && limit; /* void */ ) { n = ngx_min(b->last - p, in->buf->last - in->buf->pos); n = ngx_min(n, limit); if (b->sync) { ngx_memcpy(p, in->buf->pos, n); } p += n; in->buf->pos += n; offset += n; limit -= n; if (in->buf->pos == in->buf->last) { in = in->next; } } if (b->sync && p != b->pos) { sl = ngx_quic_split_bufs(c, cl, p - b->pos); if (sl == NGX_CHAIN_ERROR) { return NGX_ERROR; } cl->next = sl; cl->buf->sync = 0; } } return NGX_OK; } #if (NGX_DEBUG) void ngx_quic_log_frame(ngx_log_t *log, ngx_quic_frame_t *f, ngx_uint_t tx) { u_char *p, *last, *pos, *end; ssize_t n; uint64_t gap, range, largest, smallest; ngx_uint_t i; u_char buf[NGX_MAX_ERROR_STR]; p = buf; last = buf + sizeof(buf); switch (f->type) { case NGX_QUIC_FT_CRYPTO: p = ngx_slprintf(p, last, "CRYPTO len:%uL off:%uL", f->u.crypto.length, f->u.crypto.offset); #ifdef NGX_QUIC_DEBUG_FRAMES { ngx_chain_t *cl; p = ngx_slprintf(p, last, " data:"); for (cl = f->data; cl; cl = cl->next) { p = ngx_slprintf(p, last, "%*xs", cl->buf->last - cl->buf->pos, cl->buf->pos); } } #endif break; case NGX_QUIC_FT_PADDING: p = ngx_slprintf(p, last, "PADDING"); break; case NGX_QUIC_FT_ACK: case NGX_QUIC_FT_ACK_ECN: p = ngx_slprintf(p, last, "ACK n:%ui delay:%uL ", f->u.ack.range_count, f->u.ack.delay); if (f->data) { pos = f->data->buf->pos; end = f->data->buf->last; } else { pos = NULL; end = NULL; } largest = f->u.ack.largest; smallest = f->u.ack.largest - f->u.ack.first_range; if (largest == smallest) { p = ngx_slprintf(p, last, "%uL", largest); } else { p = ngx_slprintf(p, last, "%uL-%uL", largest, smallest); } for (i = 0; i < f->u.ack.range_count; i++) { n = ngx_quic_parse_ack_range(log, pos, end, &gap, &range); if (n == NGX_ERROR) { break; } pos += n; largest = smallest - gap - 2; smallest = largest - range; if (largest == smallest) { p = ngx_slprintf(p, last, " %uL", largest); } else { p = ngx_slprintf(p, last, " %uL-%uL", largest, smallest); } } if (f->type == NGX_QUIC_FT_ACK_ECN) { p = ngx_slprintf(p, last, " ECN counters ect0:%uL ect1:%uL ce:%uL", f->u.ack.ect0, f->u.ack.ect1, f->u.ack.ce); } break; case NGX_QUIC_FT_PING: p = ngx_slprintf(p, last, "PING"); break; case NGX_QUIC_FT_NEW_CONNECTION_ID: p = ngx_slprintf(p, last, "NEW_CONNECTION_ID seq:%uL retire:%uL len:%ud", f->u.ncid.seqnum, f->u.ncid.retire, f->u.ncid.len); break; case NGX_QUIC_FT_RETIRE_CONNECTION_ID: p = ngx_slprintf(p, last, "RETIRE_CONNECTION_ID seqnum:%uL", f->u.retire_cid.sequence_number); break; case NGX_QUIC_FT_CONNECTION_CLOSE: case NGX_QUIC_FT_CONNECTION_CLOSE_APP: p = ngx_slprintf(p, last, "CONNECTION_CLOSE%s err:%ui", f->type == NGX_QUIC_FT_CONNECTION_CLOSE ? "" : "_APP", f->u.close.error_code); if (f->u.close.reason.len) { p = ngx_slprintf(p, last, " %V", &f->u.close.reason); } if (f->type == NGX_QUIC_FT_CONNECTION_CLOSE) { p = ngx_slprintf(p, last, " ft:%ui", f->u.close.frame_type); } break; case NGX_QUIC_FT_STREAM: p = ngx_slprintf(p, last, "STREAM id:0x%xL", f->u.stream.stream_id); if (f->u.stream.off) { p = ngx_slprintf(p, last, " off:%uL", f->u.stream.offset); } if (f->u.stream.len) { p = ngx_slprintf(p, last, " len:%uL", f->u.stream.length); } if (f->u.stream.fin) { p = ngx_slprintf(p, last, " fin:1"); } #ifdef NGX_QUIC_DEBUG_FRAMES { ngx_chain_t *cl; p = ngx_slprintf(p, last, " data:"); for (cl = f->data; cl; cl = cl->next) { p = ngx_slprintf(p, last, "%*xs", cl->buf->last - cl->buf->pos, cl->buf->pos); } } #endif break; case NGX_QUIC_FT_MAX_DATA: p = ngx_slprintf(p, last, "MAX_DATA max_data:%uL on recv", f->u.max_data.max_data); break; case NGX_QUIC_FT_RESET_STREAM: p = ngx_slprintf(p, last, "RESET_STREAM" " id:0x%xL error_code:0x%xL final_size:0x%xL", f->u.reset_stream.id, f->u.reset_stream.error_code, f->u.reset_stream.final_size); break; case NGX_QUIC_FT_STOP_SENDING: p = ngx_slprintf(p, last, "STOP_SENDING id:0x%xL err:0x%xL", f->u.stop_sending.id, f->u.stop_sending.error_code); break; case NGX_QUIC_FT_STREAMS_BLOCKED: case NGX_QUIC_FT_STREAMS_BLOCKED2: p = ngx_slprintf(p, last, "STREAMS_BLOCKED limit:%uL bidi:%ui", f->u.streams_blocked.limit, f->u.streams_blocked.bidi); break; case NGX_QUIC_FT_MAX_STREAMS: case NGX_QUIC_FT_MAX_STREAMS2: p = ngx_slprintf(p, last, "MAX_STREAMS limit:%uL bidi:%ui", f->u.max_streams.limit, f->u.max_streams.bidi); break; case NGX_QUIC_FT_MAX_STREAM_DATA: p = ngx_slprintf(p, last, "MAX_STREAM_DATA id:0x%xL limit:%uL", f->u.max_stream_data.id, f->u.max_stream_data.limit); break; case NGX_QUIC_FT_DATA_BLOCKED: p = ngx_slprintf(p, last, "DATA_BLOCKED limit:%uL", f->u.data_blocked.limit); break; case NGX_QUIC_FT_STREAM_DATA_BLOCKED: p = ngx_slprintf(p, last, "STREAM_DATA_BLOCKED id:0x%xL limit:%uL", f->u.stream_data_blocked.id, f->u.stream_data_blocked.limit); break; case NGX_QUIC_FT_PATH_CHALLENGE: p = ngx_slprintf(p, last, "PATH_CHALLENGE data:0x%*xs", sizeof(f->u.path_challenge.data), f->u.path_challenge.data); break; case NGX_QUIC_FT_PATH_RESPONSE: p = ngx_slprintf(p, last, "PATH_RESPONSE data:0x%*xs", sizeof(f->u.path_challenge.data), f->u.path_challenge.data); break; case NGX_QUIC_FT_NEW_TOKEN: p = ngx_slprintf(p, last, "NEW_TOKEN"); break; case NGX_QUIC_FT_HANDSHAKE_DONE: p = ngx_slprintf(p, last, "HANDSHAKE DONE"); break; default: p = ngx_slprintf(p, last, "unknown type 0x%xi", f->type); break; } ngx_log_debug4(NGX_LOG_DEBUG_EVENT, log, 0, "quic frame %s %s %*s", tx ? "tx" : "rx", ngx_quic_level_name(f->level), p - buf, buf); } #endif