/* Copyright (c) 2017 - 2022 LiteSpeed Technologies Inc. See LICENSE. */ /* * lsquic_frame_writer.c -- write frames to HEADERS stream. * * The frame is first written to list of frame_buf's (frabs) and then * out to the stream. This is done because frame's size is written out * to the stream and we may not have enough room in the stream to fit * the whole frame. */ #ifndef WIN32 #include #endif #include #include #include #include #include #include #include "lshpack.h" #include "lsquic_mm.h" #include "lsquic.h" #include "lsquic_int_types.h" #include "lsquic_hash.h" #include "lsquic_conn.h" #include "lsquic_frame_writer.h" #include "lsquic_frame_common.h" #include "lsquic_frab_list.h" #include "lsquic_ev_log.h" #include "fiu-local.h" #define LSQUIC_LOGGER_MODULE LSQLM_FRAME_WRITER #define LSQUIC_LOG_CONN_ID lsquic_conn_log_cid(\ lsquic_stream_conn(fw->fw_stream)) #include "lsquic_logger.h" /* Size of the buffer passed to lshpack_enc_encode() -- this limits the size * of a single compressed header field. */ #define MAX_COMP_HEADER_FIELD_SIZE (64 * 1024) struct lsquic_frame_writer { struct lsquic_stream *fw_stream; fw_writef_f fw_writef; struct lsquic_mm *fw_mm; struct lshpack_enc *fw_henc; #if LSQUIC_CONN_STATS struct conn_stats *fw_conn_stats; #endif struct frab_list fw_fral; unsigned fw_max_frame_sz; uint32_t fw_max_header_list_sz; /* 0 means unlimited */ enum { FW_SERVER = (1 << 0), } fw_flags; }; /* RFC 7540, Section 4.2 */ #define MIN_MAX_FRAME_SIZE (1 << 14) #define MAX_MAX_FRAME_SIZE ((1 << 24) - 1) #define MAX(a, b) ((a) > (b) ? (a) : (b)) #define SETTINGS_FRAME_SZ 6 #define ABS_MIN_FRAME_SIZE MAX(SETTINGS_FRAME_SZ, \ sizeof(struct http_prio_frame)) static void * fw_alloc (void *ctx, size_t size) { return lsquic_mm_get_4k(ctx); } struct lsquic_frame_writer * lsquic_frame_writer_new (struct lsquic_mm *mm, struct lsquic_stream *stream, unsigned max_frame_sz, struct lshpack_enc *henc, fw_writef_f writef, #if LSQUIC_CONN_STATS struct conn_stats *conn_stats, #endif int is_server) { struct lsquic_frame_writer *fw; /* When frame writer is instantiated, limit the maximum size to * MIN_MAX_FRAME_SIZE. The reference implementation has this value * hardcoded and QUIC does not provide a mechanism to advertise a * different value. */ if (0 == max_frame_sz) max_frame_sz = MIN_MAX_FRAME_SIZE; else LSQ_LOG1(LSQ_LOG_WARN, "max frame size specified to be %u bytes " "-- this better be test code!", max_frame_sz); if (!is_server && max_frame_sz < ABS_MIN_FRAME_SIZE) { LSQ_LOG1(LSQ_LOG_ERROR, "max frame size must be at least %zd bytes, " "which is the size of priority information that client always " "writes", ABS_MIN_FRAME_SIZE); return NULL; } fw = calloc(1, sizeof(*fw)); if (!fw) return NULL; fw->fw_mm = mm; fw->fw_henc = henc; fw->fw_stream = stream; fw->fw_writef = writef; fw->fw_max_frame_sz = max_frame_sz; fw->fw_max_header_list_sz = 0; if (is_server) fw->fw_flags = FW_SERVER; else fw->fw_flags = 0; #if LSQUIC_CONN_STATS fw->fw_conn_stats = conn_stats; #endif lsquic_frab_list_init(&fw->fw_fral, 0x1000, fw_alloc, (void (*)(void *, void *)) lsquic_mm_put_4k, mm); return fw; } void lsquic_frame_writer_destroy (struct lsquic_frame_writer *fw) { lsquic_frab_list_cleanup(&fw->fw_fral); free(fw); } int lsquic_frame_writer_have_leftovers (const struct lsquic_frame_writer *fw) { return !lsquic_frab_list_empty(&fw->fw_fral); } int lsquic_frame_writer_flush (struct lsquic_frame_writer *fw) { struct lsquic_reader reader = { .lsqr_read = lsquic_frab_list_read, .lsqr_size = lsquic_frab_list_size, .lsqr_ctx = &fw->fw_fral, }; ssize_t nw; nw = fw->fw_writef(fw->fw_stream, &reader); if (nw >= 0) return 0; else return -1; } struct header_framer_ctx { struct lsquic_frame_writer *hfc_fw; struct { struct frame_buf *frab; unsigned short off; } hfc_header_ptr; /* Points to byte *after* current frame header */ unsigned hfc_max_frame_sz; /* Maximum frame size. We always fill it. */ unsigned hfc_cur_sz; /* Number of bytes in the current frame. */ unsigned hfc_n_frames; /* Number of frames written. */ lsquic_stream_id_t hfc_stream_id; /* Stream ID */ enum http_frame_header_flags hfc_first_flags; enum http_frame_type hfc_frame_type; }; static void hfc_init (struct header_framer_ctx *hfc, struct lsquic_frame_writer *fw, unsigned max_frame_sz, enum http_frame_type frame_type, lsquic_stream_id_t stream_id, enum http_frame_header_flags first_flags) { memset(hfc, 0, sizeof(*hfc)); hfc->hfc_fw = fw; hfc->hfc_frame_type = frame_type; hfc->hfc_stream_id = stream_id; hfc->hfc_first_flags = first_flags; hfc->hfc_max_frame_sz = max_frame_sz; hfc->hfc_cur_sz = max_frame_sz; } static void hfc_save_ptr (struct header_framer_ctx *hfc) { hfc->hfc_header_ptr.frab = TAILQ_LAST(&hfc->hfc_fw->fw_fral.fl_frabs, frame_buf_head); hfc->hfc_header_ptr.off = hfc->hfc_header_ptr.frab->frab_size; } static void hfc_terminate_frame (struct header_framer_ctx *hfc, enum http_frame_header_flags flags) { union { struct http_frame_header fh; unsigned char buf[ sizeof(struct http_frame_header) ]; } u; uint32_t stream_id; struct frame_buf *frab; /* Construct the frame */ u.fh.hfh_length[0] = hfc->hfc_cur_sz >> 16; u.fh.hfh_length[1] = hfc->hfc_cur_sz >> 8; u.fh.hfh_length[2] = hfc->hfc_cur_sz; u.fh.hfh_flags = flags; if (1 == hfc->hfc_n_frames) { u.fh.hfh_type = hfc->hfc_frame_type; u.fh.hfh_flags |= hfc->hfc_first_flags; } else u.fh.hfh_type = HTTP_FRAME_CONTINUATION; stream_id = htonl(hfc->hfc_stream_id); memcpy(u.fh.hfh_stream_id, &stream_id, sizeof(stream_id)); if (hfc->hfc_header_ptr.off >= sizeof(u.fh)) { /* Write in a single chunk */ assert(0 == memcmp("123456789", hfc->hfc_header_ptr.frab->frab_buf + hfc->hfc_header_ptr.off - sizeof(u.buf), sizeof(u.buf))); memcpy(hfc->hfc_header_ptr.frab->frab_buf + hfc->hfc_header_ptr.off - sizeof(u.buf), u.buf, sizeof(u.buf)); } else { /* Write across frab boundary */ memcpy(hfc->hfc_header_ptr.frab->frab_buf, u.buf + sizeof(u.buf) - hfc->hfc_header_ptr.off, hfc->hfc_header_ptr.off); frab = TAILQ_PREV(hfc->hfc_header_ptr.frab, frame_buf_head, frab_next); memcpy(frab->frab_buf + frab->frab_size - sizeof(u.buf) + hfc->hfc_header_ptr.off, u.buf, sizeof(u.buf) - hfc->hfc_header_ptr.off); } } static int hfc_write (struct header_framer_ctx *hfc, const void *buf, size_t sz) { const unsigned char *p = buf; unsigned avail; int s; while (sz > 0) { if (hfc->hfc_max_frame_sz == hfc->hfc_cur_sz) { if (hfc->hfc_n_frames > 0) hfc_terminate_frame(hfc, 0); s = lsquic_frab_list_write(&hfc->hfc_fw->fw_fral, "123456789", sizeof(struct http_frame_header)); if (s < 0) return s; ++hfc->hfc_n_frames; hfc_save_ptr(hfc); hfc->hfc_cur_sz = 0; } avail = hfc->hfc_max_frame_sz - hfc->hfc_cur_sz; if (sz < avail) avail = sz; if (avail) { s = lsquic_frab_list_write(&hfc->hfc_fw->fw_fral, p, avail); if (s < 0) return s; hfc->hfc_cur_sz += avail; sz -= avail; p += avail; } } return 0; } static unsigned count_uppercase (const unsigned char *buf, size_t sz) { static const unsigned char uppercase[0x100] = { ['A'] = 1, ['B'] = 1, ['C'] = 1, ['D'] = 1, ['E'] = 1, ['F'] = 1, ['G'] = 1, ['H'] = 1, ['I'] = 1, ['J'] = 1, ['K'] = 1, ['L'] = 1, ['M'] = 1, ['N'] = 1, ['O'] = 1, ['P'] = 1, ['Q'] = 1, ['R'] = 1, ['S'] = 1, ['T'] = 1, ['U'] = 1, ['V'] = 1, ['W'] = 1, ['X'] = 1, ['Y'] = 1, ['Z'] = 1, }; unsigned n_uppercase, i; n_uppercase = 0; for (i = 0; i < sz; ++i) n_uppercase += uppercase[ buf[i] ]; return n_uppercase; } static uint32_t calc_headers_size (const struct lsquic_http_headers *headers) { int i; uint32_t size = 0; for (i = 0; i < headers->count; ++i) if (headers->headers[i].buf) size += 32 + headers->headers[i].name_len + headers->headers[i].val_len; return size; } static int have_oversize_strings (const struct lsquic_http_headers *headers) { #if LSXPACK_MAX_STRLEN > LSHPACK_MAX_STRLEN int i, have; for (i = 0, have = 0; i < headers->count; ++i) { if (headers->headers[i].buf) { have |= headers->headers[i].name_len > LSHPACK_MAX_STRLEN; have |= headers->headers[i].val_len > LSHPACK_MAX_STRLEN; } } return have; #else return 0; #endif } static int check_headers_size (const struct lsquic_frame_writer *fw, const struct lsquic_http_headers *headers) { uint32_t headers_sz; headers_sz = calc_headers_size(headers); if (headers_sz <= fw->fw_max_header_list_sz) return 0; else if (fw->fw_flags & FW_SERVER) { LSQ_INFO("Sending headers larger (%u bytes) than max allowed (%u)", headers_sz, fw->fw_max_header_list_sz); return 0; } else { LSQ_INFO("Headers size %u is larger than max allowed (%u)", headers_sz, fw->fw_max_header_list_sz); errno = EMSGSIZE; return -1; } } static int check_headers_case (const struct lsquic_frame_writer *fw, const struct lsquic_http_headers *headers) { unsigned n_uppercase; int i; n_uppercase = 0; for (i = 0; i < headers->count; ++i) if (headers->headers[i].buf) n_uppercase += count_uppercase((unsigned char *) lsxpack_header_get_name(&headers->headers[i]), headers->headers[i].name_len); if (n_uppercase) { LSQ_INFO("Uppercase letters in header names"); errno = EINVAL; return -1; } return 0; } static int write_headers (struct lsquic_frame_writer *fw, const struct lsquic_http_headers *headers, struct header_framer_ctx *hfc, unsigned char *buf, const unsigned buf_sz) { unsigned char *end; int i, s; for (i = 0; i < headers->count; ++i) { if (headers->headers[i].buf == NULL) continue; end = lshpack_enc_encode(fw->fw_henc, buf, buf + buf_sz, &headers->headers[i]); if (end > buf) { s = hfc_write(hfc, buf, end - buf); if (s < 0) return s; #if LSQUIC_CONN_STATS fw->fw_conn_stats->out.headers_uncomp += headers->headers[i].name_len + headers->headers[i].val_len; fw->fw_conn_stats->out.headers_comp += end - buf; #endif } else { /* Ignore errors, matching HTTP2 behavior in our server code */ } } return 0; } int lsquic_frame_writer_write_headers (struct lsquic_frame_writer *fw, lsquic_stream_id_t stream_id, const struct lsquic_http_headers *headers, int eos, unsigned weight) { struct header_framer_ctx hfc; int s; struct http_prio_frame prio_frame; enum http_frame_header_flags flags; unsigned char *buf; /* Internal function: weight must be valid here */ assert(weight >= 1 && weight <= 256); if (fw->fw_max_header_list_sz && 0 != check_headers_size(fw, headers)) return -1; if (0 != check_headers_case(fw, headers)) return -1; if (have_oversize_strings(headers)) return -1; if (eos) flags = HFHF_END_STREAM; else flags = 0; if (!(fw->fw_flags & FW_SERVER)) flags |= HFHF_PRIORITY; hfc_init(&hfc, fw, fw->fw_max_frame_sz, HTTP_FRAME_HEADERS, stream_id, flags); if (!(fw->fw_flags & FW_SERVER)) { memset(&prio_frame.hpf_stream_id, 0, sizeof(prio_frame.hpf_stream_id)); prio_frame.hpf_weight = weight - 1; s = hfc_write(&hfc, &prio_frame, sizeof(struct http_prio_frame)); if (s < 0) return s; } buf = malloc(MAX_COMP_HEADER_FIELD_SIZE); if (!buf) return -1; s = write_headers(fw, headers, &hfc, buf, MAX_COMP_HEADER_FIELD_SIZE); free(buf); if (0 == s) { EV_LOG_GENERATED_HTTP_HEADERS(LSQUIC_LOG_CONN_ID, stream_id, fw->fw_flags & FW_SERVER, &prio_frame, headers); hfc_terminate_frame(&hfc, HFHF_END_HEADERS); return lsquic_frame_writer_flush(fw); } else return s; } int lsquic_frame_writer_write_promise (struct lsquic_frame_writer *fw, lsquic_stream_id_t stream_id64, lsquic_stream_id_t promised_stream_id64, const struct lsquic_http_headers *headers) { uint32_t stream_id = stream_id64; uint32_t promised_stream_id = promised_stream_id64; struct header_framer_ctx hfc; struct http_push_promise_frame push_frame; unsigned char *buf; int s; fiu_return_on("frame_writer/writer_promise", -1); if (fw->fw_max_header_list_sz && 0 != check_headers_size(fw, headers)) return -1; if (0 != check_headers_case(fw, headers)) return -1; if (have_oversize_strings(headers)) return -1; hfc_init(&hfc, fw, fw->fw_max_frame_sz, HTTP_FRAME_PUSH_PROMISE, stream_id, 0); promised_stream_id = htonl(promised_stream_id); memcpy(push_frame.hppf_promised_id, &promised_stream_id, 4); s = hfc_write(&hfc, &push_frame, sizeof(struct http_push_promise_frame)); if (s < 0) return s; buf = malloc(MAX_COMP_HEADER_FIELD_SIZE); if (!buf) return -1; s = write_headers(fw, headers, &hfc, buf, MAX_COMP_HEADER_FIELD_SIZE); if (s != 0) { free(buf); return -1; } free(buf); EV_LOG_GENERATED_HTTP_PUSH_PROMISE(LSQUIC_LOG_CONN_ID, stream_id, htonl(promised_stream_id), headers); hfc_terminate_frame(&hfc, HFHF_END_HEADERS); return lsquic_frame_writer_flush(fw); } void lsquic_frame_writer_max_header_list_size (struct lsquic_frame_writer *fw, uint32_t max_size) { LSQ_DEBUG("set max_header_list_sz to %u", max_size); fw->fw_max_header_list_sz = max_size; } static int write_settings (struct lsquic_frame_writer *fw, const struct lsquic_http2_setting *settings, unsigned n_settings) { struct http_frame_header fh; unsigned payload_length; uint32_t val; uint16_t id; int s; payload_length = n_settings * 6; memset(&fh, 0, sizeof(fh)); fh.hfh_type = HTTP_FRAME_SETTINGS; fh.hfh_length[0] = payload_length >> 16; fh.hfh_length[1] = payload_length >> 8; fh.hfh_length[2] = payload_length; s = lsquic_frab_list_write(&fw->fw_fral, &fh, sizeof(fh)); if (s != 0) return s; do { id = htons(settings->id); val = htonl(settings->value); if (0 != (s = lsquic_frab_list_write(&fw->fw_fral, &id, sizeof(id))) || 0 != (s = lsquic_frab_list_write(&fw->fw_fral, &val, sizeof(val)))) return s; EV_LOG_CONN_EVENT(LSQUIC_LOG_CONN_ID, "wrote HTTP SETTINGS frame: " "%s=%"PRIu32, lsquic_http_setting_id2str(settings->id), settings->value); ++settings; } while (--n_settings); return 0; } int lsquic_frame_writer_write_settings (struct lsquic_frame_writer *fw, const struct lsquic_http2_setting *settings, unsigned n_settings) { unsigned settings_per_frame; unsigned n; if (0 == n_settings) { errno = EINVAL; return -1; } settings_per_frame = fw->fw_max_frame_sz / SETTINGS_FRAME_SZ; n = 0; do { if (settings_per_frame > n_settings - n) settings_per_frame = n_settings - n; if (0 != write_settings(fw, &settings[n], settings_per_frame)) return -1; n += settings_per_frame; } while (n < n_settings); return lsquic_frame_writer_flush(fw); } int lsquic_frame_writer_write_priority (struct lsquic_frame_writer *fw, lsquic_stream_id_t stream_id64, int exclusive, lsquic_stream_id_t stream_dep_id64, unsigned weight) { uint32_t stream_id = stream_id64; uint32_t stream_dep_id = stream_dep_id64; unsigned char buf[ sizeof(struct http_frame_header) + sizeof(struct http_prio_frame) ]; struct http_frame_header *fh = (void *) &buf[0]; struct http_prio_frame *prio_frame = (void *) &buf[sizeof(*fh)]; int s; if (stream_dep_id & (1UL << 31)) { LSQ_WARN("stream ID too high (%u): cannot write PRIORITY frame", stream_dep_id); return -1; } if (weight < 1 || weight > 256) return -1; memset(fh, 0, sizeof(*fh)); fh->hfh_type = HTTP_FRAME_PRIORITY; fh->hfh_length[2] = sizeof(struct http_prio_frame); stream_id = htonl(stream_id); memcpy(fh->hfh_stream_id, &stream_id, 4); stream_dep_id |= !!exclusive << 31; stream_id = htonl(stream_dep_id); memcpy(prio_frame->hpf_stream_id, &stream_id, 4); prio_frame->hpf_weight = weight - 1; s = lsquic_frab_list_write(&fw->fw_fral, buf, sizeof(buf)); if (s != 0) return s; EV_LOG_CONN_EVENT(LSQUIC_LOG_CONN_ID, "wrote HTTP PRIORITY frame: " "stream %"PRIu32"; weight: %u; exclusive: %d", htonl(stream_id), weight, !!exclusive); return lsquic_frame_writer_flush(fw); } size_t lsquic_frame_writer_mem_used (const struct lsquic_frame_writer *fw) { size_t size; size = sizeof(*fw) + lsquic_frab_list_mem_used(&fw->fw_fral) - sizeof(fw->fw_fral); return size; }