diff options
Diffstat (limited to 'serve/deliver.c')
| -rw-r--r-- | serve/deliver.c | 716 |
1 files changed, 716 insertions, 0 deletions
diff --git a/serve/deliver.c b/serve/deliver.c new file mode 100644 index 0000000..0d3da64 --- /dev/null +++ b/serve/deliver.c @@ -0,0 +1,716 @@ +#define _POSIX_C_SOURCE 200809L +#include "deliver.h" +#include "message-json.h" +#include "module-text.h" +#include <errno.h> +#include <netdb.h> +#include <netinet/in.h> +#include <netinet/tcp.h> +#include <openssl/ssl.h> +#include <openssl/x509v3.h> +#include <arpa/inet.h> +#include <pthread.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <strings.h> +#include <sys/socket.h> +#include <sys/time.h> +#include <time.h> +#include <unistd.h> + +enum { TIMEOUT_S = 10, FIRST_PAUSE_MS = 100, LONGEST_PAUSE_MS = 10000, GROUPS = PURE_MODULE_NAME / 2, BATCH_MOST = 256, + ANSWER_MOST = 1 << 20 }; +enum { DELIVERED, AGAIN, REFUSED_BY_PEER, TLS_FAILED, ANSWER_UNREAD }; + +typedef struct { char *body; size_t size; uint64_t seq; unsigned char *sent; size_t sent_size; } Pending; +/* An answer made into its input's message: a table of the fields' starts and + * sizes (u32le), then the payload from its prefix on. */ +typedef struct { uint64_t seq; unsigned char *bytes; size_t size, table; } Answer; + +struct PureWire { + const PureModule *module; + uint32_t output; + char host[256], port[8], path[1024], source[PURE_SOURCE + 1]; + pthread_mutex_t lock; + pthread_cond_t changed; + Pending *queue; /* the sends to deliver, in order, from head */ + size_t head, count, capacity; + uint64_t queued, delivered, attempts, deliveries; + unsigned batch; /* how many a request may carry, as the receiver said (X-Pure-Batch); 0: one */ + bool stopping, started, stuck; + pthread_t thread; + void (*notify)(void *); + void *context; + int fd; /* the connection kept for the next send, or -1; changed under the lock */ + bool tls; /* https: the connection is TLS */ + SSL *ssl; /* its TLS session */ + int answer_input; /* the input answers become events of, or -1 */ + Answer *answers; /* made, for the owner to take in order */ + size_t answer_head, answer_count, answer_capacity; + Answer taken; /* the one the owner took last, kept until it takes the next */ + uint32_t placed[2 * PURE_MODULE_FIELDS]; +}; + +/* ---- TLS: one client context, verifying the receiver's certificate against + * the system's CAs or the file pure_wire_trust named, and its name. */ +static pthread_once_t tls_once = PTHREAD_ONCE_INIT; +static SSL_CTX *tls_context; +static const char *tls_ca; + +void pure_wire_trust(const char *ca_file) { tls_ca = ca_file; } + +static void make_tls_context(void) { + SSL_CTX *context = SSL_CTX_new(TLS_client_method()); + if (!context) return; + if (!SSL_CTX_set_min_proto_version(context, TLS1_2_VERSION) || + !(tls_ca ? SSL_CTX_load_verify_locations(context, tls_ca, NULL) : SSL_CTX_set_default_verify_paths(context))) { + SSL_CTX_free(context); + return; + } + SSL_CTX_set_verify(context, SSL_VERIFY_PEER, NULL); + SSL_CTX_set_mode(context, SSL_MODE_AUTO_RETRY); + tls_context = context; +} + +/* ---- A send as JSON: its fields in order, a group's fields as an object. */ + +typedef struct { char *bytes; size_t size, capacity; bool failed; } Text; + +static void put(Text *t, const void *bytes, size_t size) { + if (t->failed) return; + if (size > t->capacity - t->size) { + size_t capacity = t->capacity ? t->capacity : 256; + while (size > capacity - t->size) capacity *= 2; + char *grown = realloc(t->bytes, capacity); + if (!grown) { t->failed = true; return; } + t->bytes = grown; + t->capacity = capacity; + } + memcpy(t->bytes + t->size, bytes, size); + t->size += size; +} + +static void put_string(Text *t, const unsigned char *bytes, size_t size) { + put(t, "\"", 1); + size_t run = 0; + for (size_t i = 0; i < size; ++i) { + unsigned char b = bytes[i]; + if (b != '"' && b != '\\' && b >= 0x20) continue; + put(t, bytes + run, i - run); + char escaped[8]; + if (b == '"' || b == '\\') put(t, (char[]){'\\', (char)b}, 2); + else put(t, escaped, (size_t)snprintf(escaped, sizeof(escaped), "\\u%04x", b)); + run = i + 1; + } + put(t, bytes + run, size - run); + put(t, "\"", 1); +} + +static uint32_t read_u32(const unsigned char *p) { return p[0] | p[1] << 8 | (uint32_t)p[2] << 16 | (uint32_t)p[3] << 24; } + +/* The group a field is in: the length of its name before the last dot (0: none). */ +static size_t group_of(const char *name) { + const char *dot = strrchr(name, '.'); + return dot ? (size_t)(dot - name) : 0; +} + +/* Whether the group path open (length open_size) holds the group of name (length size). */ +static bool holds(const char *open, size_t open_size, const char *name, size_t size) { + return open_size <= size && !memcmp(open, name, open_size) && (open_size == size || !open_size || name[open_size] == '.'); +} + +static bool encode(const PureWire *w, PureSpan payload, Text *t) { + const PureModule *m = w->module; + const PureInputShape *shape = &m->input[w->output]; + if (payload.size < shape->prefix) return false; + char open[PURE_MODULE_NAME] = ""; + size_t open_size = 0, at = shape->prefix; + unsigned depth = 0; + bool first[GROUPS + 1] = {true}; + put(t, "{", 1); + for (uint32_t f = 0; f < shape->field_count; ++f) { + const PureField *field = &m->field[shape->field_start + f]; + size_t group = group_of(field->name); + while (depth && !holds(open, open_size, field->name, group)) { + put(t, "}", 1); + --depth; + open_size = group_of(open) < open_size ? group_of(open) : 0; + open[open_size] = 0; + } + while (open_size < group) { + size_t start = open_size ? open_size + 1 : 0, end = start; + while (end < group && field->name[end] != '.') ++end; + if (!first[depth]) put(t, ",", 1); + first[depth] = false; + put_string(t, (const unsigned char *)field->name + start, end - start); + put(t, ":{", 2); + first[++depth] = true; + memcpy(open, field->name, end); + open[open_size = end] = 0; + } + if (!first[depth]) put(t, ",", 1); + first[depth] = false; + const char *key = field->name + (group ? group + 1 : 0); + put_string(t, (const unsigned char *)key, strlen(key)); + put(t, ":", 1); + char digits[32]; + if (field->type == PURE_FIELD_U32) { + put(t, digits, (size_t)snprintf(digits, sizeof(digits), "%u", (unsigned)read_u32(payload.data + field->offset))); + } else if (field->type == PURE_FIELD_NUMBER) { + uint64_t bits = read_u32(payload.data + field->offset) | (uint64_t)read_u32(payload.data + field->offset + 4) << 32; + double value; + memcpy(&value, &bits, sizeof(value)); + put(t, digits, pure_format_number(value, digits)); + } else { + size_t size = field->offset == PURE_FIELD_REST ? payload.size - at : read_u32(payload.data + field->offset); + if (size > payload.size - at) return false; + PureSpan value = {payload.data + at, size}; + if (!pure_utf8_valid(value)) return false; /* bytes that are not text have no JSON form */ + put_string(t, value.data, size); + at += size; + } + } + while (depth--) put(t, "}", 1); + put(t, "}", 1); + return !t->failed; +} + +/* ---- The wire. */ + +PureWire *pure_wire_open(const PureModule *m, const char *output, const char *url, const char *source, + char *error, size_t size) { + int index = pure_module_input(m, output); + if (index < 0 || m->input[index].kind != PURE_KIND_OUTPUT) { + snprintf(error, size, "no output '%s'", output); + return NULL; + } + /* A group's fields are together, so each group is one object. */ + const PureInputShape *shape = &m->input[index]; + for (uint32_t f = 1; f < shape->field_count; ++f) { + const char *name = m->field[shape->field_start + f].name; + for (uint32_t e = 0; e + 1 < f; ++e) { + const char *earlier = m->field[shape->field_start + e].name, *between = m->field[shape->field_start + f - 1].name; + size_t shared = 0; + while (earlier[shared] && earlier[shared] == name[shared]) ++shared; + while (shared && earlier[shared - 1] != '.') --shared; /* the groups both are in */ + if (shared && strncmp(between, name, shared)) { + snprintf(error, size, "the fields of output '%s' in one group are not together", output); + return NULL; + } + } + } + size_t length = strlen(source); + if (!length || length > PURE_SOURCE) { + snprintf(error, size, "a source name has 1 to %d bytes", PURE_SOURCE); + return NULL; + } + bool tls = !strncmp(url, "https://", 8); + if (!tls && strncmp(url, "http://", 7)) { + snprintf(error, size, "a URL is http[s]://host[:port]/path"); + return NULL; + } + if (tls) { + pthread_once(&tls_once, make_tls_context); + if (!tls_context) { + snprintf(error, size, "no TLS context: %s cannot be read", tls_ca ? tls_ca : "the system's CAs"); + return NULL; + } + } + const char *host = url + (tls ? 8 : 7), *slash = strchr(host, '/'), *colon = memchr(host, ':', slash ? (size_t)(slash - host) : strlen(host)); + const char *host_end = colon ? colon : slash ? slash : host + strlen(host); + const char *port = colon ? colon + 1 : tls ? "443" : "80"; + size_t port_size = colon ? (size_t)((slash ? slash : host + strlen(host)) - port) : strlen(port); + if (host_end == host || (size_t)(host_end - host) >= 256 || !port_size || port_size >= 8 || + (slash && strlen(slash) >= 1024)) { + snprintf(error, size, "a URL is http://host[:port]/path"); + return NULL; + } + PureWire *w = calloc(1, sizeof(*w)); + if (!w) { snprintf(error, size, "out of memory"); return NULL; } + w->module = m; + w->output = (uint32_t)index; + memcpy(w->host, host, (size_t)(host_end - host)); + memcpy(w->port, port, port_size); + snprintf(w->path, sizeof(w->path), "%s", slash ? slash : "/"); + memcpy(w->source, source, length + 1); + w->fd = -1; + w->tls = tls; + w->answer_input = -1; + pthread_mutex_init(&w->lock, NULL); + pthread_cond_init(&w->changed, NULL); + return w; +} + +uint32_t pure_wire_output(const PureWire *w) { return w->output; } + +bool pure_wire_reply(PureWire *w, uint32_t input, char *error, size_t size) { + const PureModule *m = w->module; + if (input >= m->inputs || m->input[input].kind != PURE_KIND_MESSAGE || m->input[input].keyed) { + snprintf(error, size, "an answer goes to a message input without a key"); + return false; + } + w->answer_input = (int)input; + return true; +} + +bool pure_wire_answer(PureWire *w, PureWireAnswer *out) { + free(w->taken.bytes); + w->taken = (Answer){0}; + pthread_mutex_lock(&w->lock); + bool some = w->answer_count > 0; + if (some) { + w->taken = w->answers[w->answer_head++]; + --w->answer_count; + w->delivered = w->taken.seq; /* trimmed after the owner applies it */ + } + pthread_mutex_unlock(&w->lock); + if (!some) return false; + const PureInputShape *in = &w->module->input[w->answer_input]; + for (size_t i = 0; i < 2 * (size_t)in->field_count; ++i) w->placed[i] = read_u32(w->taken.bytes + 4 * i); + *out = (PureWireAnswer){(uint32_t)w->answer_input, w->taken.seq, + {w->taken.bytes + w->taken.table, w->taken.size - w->taken.table}, w->placed, w->source}; + return true; +} +uint64_t pure_wire_queued(const PureWire *w) { return w->queued; } + +uint64_t pure_wire_delivered(PureWire *w) { + pthread_mutex_lock(&w->lock); + uint64_t delivered = w->delivered; + pthread_mutex_unlock(&w->lock); + return delivered; +} + +void pure_wire_counts(PureWire *w, uint64_t *delivered, uint64_t *attempts) { + pthread_mutex_lock(&w->lock); + *delivered = w->deliveries; + *attempts = w->attempts; + pthread_mutex_unlock(&w->lock); +} + +bool pure_wire_queue(PureWire *w, uint64_t seq, PureSpan payload) { + if (w->stuck) return false; + Text t = {0}; + if (!encode(w, payload, &t)) { + free(t.bytes); + w->stuck = true; + fprintf(stderr, "{\"wire\":\"%s\",\"seq\":%llu,\"error\":\"no JSON form: its bytes are not text\"}\n", w->source, + (unsigned long long)seq); + return false; + } + pthread_mutex_lock(&w->lock); + if (w->head + w->count == w->capacity) { + if (w->head) { + memmove(w->queue, w->queue + w->head, w->count * sizeof(*w->queue)); + w->head = 0; + } else { + size_t capacity = w->capacity ? 2 * w->capacity : 16; + Pending *grown = realloc(w->queue, capacity * sizeof(*grown)); + if (!grown) { + pthread_mutex_unlock(&w->lock); + free(t.bytes); + return false; /* it stays in the outbox: queued after the next save */ + } + w->queue = grown; + w->capacity = capacity; + } + } + unsigned char *sent = NULL; + if (w->answer_input >= 0 && !(sent = malloc(payload.size ? payload.size : 1))) { + pthread_mutex_unlock(&w->lock); + free(t.bytes); + return false; + } + if (sent && payload.size) memcpy(sent, payload.data, payload.size); + w->queue[w->head + w->count++] = (Pending){t.bytes, t.size, seq, sent, payload.size}; + w->queued = seq; + pthread_cond_signal(&w->changed); + pthread_mutex_unlock(&w->lock); + return true; +} + +/* ---- HTTP/1.1, one request at a time on a kept connection. */ + +typedef struct { PureWire *wire; char bytes[4096]; size_t at, end; } Reader; + +static bool fill(Reader *r) { + if (r->at == r->end) r->at = r->end = 0; + if (r->end == sizeof(r->bytes)) return false; + PureWire *w = r->wire; + ssize_t n; + if (w->ssl) n = SSL_read(w->ssl, r->bytes + r->end, (int)(sizeof(r->bytes) - r->end)); + else do n = recv(w->fd, r->bytes + r->end, sizeof(r->bytes) - r->end, 0); while (n < 0 && errno == EINTR); + if (n <= 0) return false; +#ifdef TCP_QUICKACK + /* Acknowledge at once: a server that writes an answer in pieces holds the + * next piece until the first is acknowledged (Nagle), which a delayed + * acknowledgement would stall for 40 ms. The flag does not stay set. */ + int one = 1; + setsockopt(w->fd, IPPROTO_TCP, TCP_QUICKACK, &one, sizeof(one)); +#endif + r->end += (size_t)n; + return true; +} + +/* A line without its CRLF, in line (at most size - 1 bytes). */ +static bool read_line(Reader *r, char *line, size_t size) { + for (;;) { + char *end = memchr(r->bytes + r->at, '\n', r->end - r->at); + if (end) { + size_t length = (size_t)(end - (r->bytes + r->at)); + if (length && end[-1] == '\r') --length; + if (length >= size) return false; + memcpy(line, r->bytes + r->at, length); + line[length] = 0; + r->at = (size_t)(end - r->bytes) + 1; + return true; + } + if (r->at) { + memmove(r->bytes, r->bytes + r->at, r->end - r->at); + r->end -= r->at; + r->at = 0; + } + if (!fill(r)) return false; + } +} + +/* size bytes of the body: kept in into (up to ANSWER_MOST), or skipped when it is NULL. */ +static bool take(Reader *r, uint64_t size, Text *into) { + if (into && size > ANSWER_MOST - into->size) return false; + while (size) { + if (r->at == r->end && !fill(r)) return false; + size_t n = r->end - r->at < size ? r->end - r->at : (size_t)size; + if (into) put(into, r->bytes + r->at, n); + r->at += n; + size -= n; + } + return !into || !into->failed; +} + +static bool send_all(PureWire *w, const char *bytes, size_t size) { + while (size) { + ssize_t n = w->ssl ? SSL_write(w->ssl, bytes, (int)(size < INT32_MAX ? size : INT32_MAX)) : + send(w->fd, bytes, size, MSG_NOSIGNAL); + if (n < 0 && !w->ssl && errno == EINTR) continue; + if (n <= 0) return false; + bytes += n; + size -= (size_t)n; + } + return true; +} + +/* TLS over a connected socket: the receiver's certificate must name the host + * (a DNS name, or an IP address written as one). */ +static SSL *start_tls(const PureWire *w, int fd) { + SSL *ssl = SSL_new(tls_context); + if (!ssl) return NULL; + unsigned char address[16]; + bool literal = inet_pton(AF_INET, w->host, address) == 1 || inet_pton(AF_INET6, w->host, address) == 1; + bool named = literal ? X509_VERIFY_PARAM_set1_ip_asc(SSL_get0_param(ssl), w->host) == 1 : + SSL_set_tlsext_host_name(ssl, w->host) == 1 && SSL_set1_host(ssl, w->host) == 1; + if (!named || SSL_set_fd(ssl, fd) != 1 || SSL_connect(ssl) != 1 || SSL_get_verify_result(ssl) != X509_V_OK) { + SSL_free(ssl); + return NULL; + } + return ssl; +} + +static int connect_to(const PureWire *w) { + struct addrinfo hints = {.ai_family = AF_UNSPEC, .ai_socktype = SOCK_STREAM}, *list; + if (getaddrinfo(w->host, w->port, &hints, &list)) return -1; + int fd = -1; + for (struct addrinfo *a = list; a && fd < 0; a = a->ai_next) { + fd = socket(a->ai_family, a->ai_socktype | SOCK_CLOEXEC, a->ai_protocol); + if (fd < 0) continue; + struct timeval limit = {TIMEOUT_S, 0}; + int one = 1; + setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &limit, sizeof(limit)); + setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, &limit, sizeof(limit)); + setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one)); + if (connect(fd, a->ai_addr, a->ai_addrlen)) { + close(fd); + fd = -1; + } + } + freeaddrinfo(list); + return fd; +} + +static void drop_connection(PureWire *w) { + pthread_mutex_lock(&w->lock); + if (w->ssl) SSL_free(w->ssl); + if (w->fd >= 0) close(w->fd); + w->ssl = NULL; + w->fd = -1; + pthread_mutex_unlock(&w->lock); +} + +/* A fault a Pure receiver answers when its app refused the message. */ +static bool refusal(const char *error) { + static const char *const faults[] = {"divide", "non_finite", "clamp", "limit", "not_found", "encoding", "exists"}; + for (size_t i = 0; i < sizeof(faults) / sizeof(*faults); ++i) if (!strcmp(error, faults[i])) return true; + return false; +} + +/* The answer to one request: its status, whether a Pure receiver refused it, + * and whether the connection may carry the next. */ +static bool read_answer(PureWire *w, int *status, bool *refused, bool *keep, unsigned *batch, Text *body) { + Reader r = {.wire = w}; + char line[1024]; + if (!read_line(&r, line, sizeof(line)) || strncmp(line, "HTTP/1.", 7) || strlen(line) < 12) return false; + *status = atoi(line + 9); + *keep = line[7] == '1'; + *refused = false; + uint64_t length = 0; + bool sized = false, chunked = false; + while (read_line(&r, line, sizeof(line))) { + if (!*line) { + if (chunked) { + for (;;) { + uint64_t chunk; + if (!read_line(&r, line, sizeof(line))) return false; + chunk = strtoull(line, NULL, 16); + if (!chunk) break; + if (!take(&r, chunk, body) || !read_line(&r, line, sizeof(line))) return false; + } + while (read_line(&r, line, sizeof(line)) && *line) {} + return true; + } + if (*status == 204 || *status == 304 || *status < 200) return true; + if (sized) return take(&r, length, body); + *keep = false; /* the body runs to the close */ + while (fill(&r)) { + if (body && !take(&r, r.end - r.at, body)) return false; + r.at = r.end; + } + return true; + } + char *value = strchr(line, ':'); + if (!value) return false; + *value++ = 0; + while (*value == ' ' || *value == '\t') ++value; + if (!strcasecmp(line, "Content-Length")) { length = strtoull(value, NULL, 10); sized = true; } + else if (!strcasecmp(line, "Transfer-Encoding")) chunked = !strcasecmp(value, "chunked"); + else if (!strcasecmp(line, "Connection")) *keep = strcasecmp(value, "close") != 0 && *keep; + else if (!strcasecmp(line, "X-Pure-Error")) *refused = refusal(value); + else if (!strcasecmp(line, "X-Pure-Batch")) *batch = (unsigned)strtoul(value, NULL, 10); + } + return false; +} + +static void write_u32(unsigned char *p, uint32_t v) { for (unsigned i = 0; i < 4; ++i) p[i] = (unsigned char)(v >> (8 * i)); } + +/* The answer (status, body) to the send p as a message of the answer input: + * fields from the body's JSON object by name, others skipped; a field the + * body lacks from the send's field of that name and type; a u32 field named + * http_status from the status. False when a field has none of these. */ +static bool form_answer(const PureWire *w, int status, const Text *body, const Pending *p, Answer *out) { + const PureModule *m = w->module; + const PureInputShape *in = &m->input[w->answer_input], *sent = &m->input[w->output]; + size_t table = 8 * (size_t)in->field_count, total = table + in->prefix + body->size + p->sent_size; + unsigned char *bytes = calloc(1, total ? total : 1); + if (!bytes) return false; + unsigned char *prefix = bytes + table, *text = prefix + in->prefix, *copy = text + body->size; + if (body->size) memcpy(text, body->bytes, body->size); + if (p->sent_size) memcpy(copy, p->sent, p->sent_size); + PureJsonMessage message = {.module = m, .shape = in, .payload = prefix, .table = bytes, .lenient = true}; + size_t at = pure_json_space(text, 0, body->size); + if (at < body->size && text[at] == '{' && pure_json_message(&message, text, body->size, &at)) { + free(bytes); + return false; + } + for (uint32_t f = 0; f < in->field_count; ++f) { + if (message.seen[f]) continue; + const PureField *field = &m->field[in->field_start + f]; + if (field->type == PURE_FIELD_U32 && !strcmp(field->name, "http_status")) { + write_u32(prefix + field->offset, (uint32_t)status); + continue; + } + /* The send's field of the same name and type, and where its bytes are. */ + size_t start = sent->prefix, length = 0; + const PureField *from = NULL; + for (uint32_t g = 0; g < sent->field_count && !from; ++g) { + const PureField *other = &m->field[sent->field_start + g]; + bool variable = other->type == PURE_FIELD_BYTES || other->type == PURE_FIELD_TEXT; + if (variable) length = other->offset == PURE_FIELD_REST ? p->sent_size - start : read_u32(p->sent + other->offset); + if (!strcmp(other->name, field->name) && other->type == field->type) from = other; + else if (variable) start += length; + } + bool variable = field->type == PURE_FIELD_BYTES || field->type == PURE_FIELD_TEXT; + if (!from || (variable && (start > p->sent_size || length > p->sent_size - start))) { + free(bytes); + return false; + } + if (field->type == PURE_FIELD_U32 || field->type == PURE_FIELD_NUMBER) + memcpy(prefix + field->offset, p->sent + from->offset, field->type == PURE_FIELD_U32 ? 4 : 8); + else { + write_u32(bytes + 8 * f, (uint32_t)(copy + start - prefix)); + write_u32(bytes + 8 * f + 4, (uint32_t)length); + } + } + *out = (Answer){p->seq, bytes, total, table}; + return true; +} + +/* One request for count sends from p (numbered in a row): one object, or + * an array of them for a receiver that takes batches. A final answer to a + * send whose answers are wired is made into *answer. */ +static int post(PureWire *w, const Pending *p, unsigned count, Answer *answer) { + size_t body = count > 1 ? count + 1 : 0; + for (unsigned i = 0; i < count; ++i) body += p[i].size; + char head[2048], batch[32] = ""; + if (count > 1) snprintf(batch, sizeof(batch), "X-Pure-Count: %u\r\n", count); + int size = snprintf(head, sizeof(head), + "POST %s HTTP/1.1\r\nHost: %s:%s\r\nContent-Type: application/json\r\nContent-Length: %zu\r\n" + "X-Pure-Source: %s\r\nX-Pure-Sequence: %llu\r\n%sIdempotency-Key: %s-%llu\r\n\r\n", + w->path, w->host, w->port, body, w->source, (unsigned long long)p->seq, batch, w->source, + (unsigned long long)p->seq); + /* A kept connection the peer closed is tried once more on a new one. */ + for (int attempt = 0; attempt < 2; ++attempt) { + bool fresh = w->fd < 0; + if (fresh) { + int fd = connect_to(w); + if (fd < 0) return AGAIN; + pthread_mutex_lock(&w->lock); + w->fd = fd; + bool stopping = w->stopping; + pthread_mutex_unlock(&w->lock); + if (stopping) return AGAIN; + SSL *ssl = w->tls ? start_tls(w, fd) : NULL; + if (w->tls && !ssl) { + drop_connection(w); + return TLS_FAILED; + } + pthread_mutex_lock(&w->lock); + w->ssl = ssl; + pthread_mutex_unlock(&w->lock); + } + int status; + bool refused, keep, sent = send_all(w, head, (size_t)size); + unsigned batch_size = 0; + Text body = {0}; + for (unsigned i = 0; sent && i < count; ++i) + sent = (!i || count == 1 || send_all(w, ",", 1)) && (i || count == 1 || send_all(w, "[", 1)) && + send_all(w, p[i].body, p[i].size); + if (sent && count > 1) sent = send_all(w, "]", 1); + if (!sent || !read_answer(w, &status, &refused, &keep, &batch_size, w->answer_input >= 0 ? &body : NULL)) { + free(body.bytes); + drop_connection(w); + if (fresh) return AGAIN; + continue; + } + if (!keep) drop_connection(w); + if (batch_size && w->answer_input < 0) w->batch = batch_size; + if (status == 408 || status == 429 || status >= 500) { + free(body.bytes); + return AGAIN; + } + if (w->answer_input >= 0 && status >= 200 && status < 500) { /* a final answer: the app hears it */ + bool formed = form_answer(w, status, &body, p, answer); + free(body.bytes); + return formed ? DELIVERED : ANSWER_UNREAD; + } + free(body.bytes); + if ((status >= 200 && status < 300) || (status >= 400 && status < 500 && refused)) return DELIVERED; + return REFUSED_BY_PEER; + } + return AGAIN; +} + +static void *deliver(void *context) { + PureWire *w = context; + long pause_ms = 0; + uint64_t reported = 0; + pthread_mutex_lock(&w->lock); + for (;;) { + while (!w->stopping && !w->count) pthread_cond_wait(&w->changed, &w->lock); + if (w->stopping) break; + /* As many as the receiver takes at once; their bodies stay put while + * the queue only grows behind them. */ + unsigned count = w->batch > 1 ? (unsigned)(w->count < w->batch ? w->count : w->batch) : 1; + Pending next[BATCH_MOST]; + if (count > BATCH_MOST) count = BATCH_MOST; + memcpy(next, w->queue + w->head, count * sizeof(*next)); + ++w->attempts; + pthread_mutex_unlock(&w->lock); + Answer answer = {0}; + int outcome = post(w, next, count, &answer); + pthread_mutex_lock(&w->lock); + if (outcome == DELIVERED && answer.bytes) { /* for the owner, who then counts it delivered */ + if (w->answer_head + w->answer_count == w->answer_capacity) { + if (w->answer_head) { + memmove(w->answers, w->answers + w->answer_head, w->answer_count * sizeof(*w->answers)); + w->answer_head = 0; + } else { + size_t capacity = w->answer_capacity ? 2 * w->answer_capacity : 16; + Answer *grown = realloc(w->answers, capacity * sizeof(*grown)); + if (!grown) { free(answer.bytes); outcome = AGAIN; } + else { w->answers = grown; w->answer_capacity = capacity; } + } + } + if (outcome == DELIVERED) w->answers[w->answer_head + w->answer_count++] = answer; + } + if (outcome == DELIVERED) { + for (unsigned i = 0; i < count; ++i) { + free(w->queue[w->head + i].body); + free(w->queue[w->head + i].sent); + } + w->head += count; + w->count -= count; + if (!answer.bytes) w->delivered = next[count - 1].seq; + w->deliveries += count; + pause_ms = 0; + pthread_mutex_unlock(&w->lock); + if (w->notify) w->notify(w->context); + pthread_mutex_lock(&w->lock); + continue; + } + if (outcome != AGAIN && reported != next[0].seq) { + fprintf(stderr, "{\"wire\":\"%s\",\"seq\":%llu,\"error\":\"%s\"}\n", w->source, + (unsigned long long)next[0].seq, outcome == TLS_FAILED ? "the receiver's certificate is not trusted; trying again" : + outcome == ANSWER_UNREAD ? "its answer does not make the answer input's message; trying again" : + "the receiver does not take it; trying again"); + reported = next[0].seq; + } + pause_ms = outcome != AGAIN ? LONGEST_PAUSE_MS : pause_ms ? 2 * pause_ms : FIRST_PAUSE_MS; + if (pause_ms > LONGEST_PAUSE_MS) pause_ms = LONGEST_PAUSE_MS; + struct timespec until; + clock_gettime(CLOCK_REALTIME, &until); + until.tv_sec += pause_ms / 1000; + until.tv_nsec += (pause_ms % 1000) * 1000000; + if (until.tv_nsec >= 1000000000) { ++until.tv_sec; until.tv_nsec -= 1000000000; } + while (!w->stopping && pthread_cond_timedwait(&w->changed, &w->lock, &until) == 0) {} + } + pthread_mutex_unlock(&w->lock); + return NULL; +} + +bool pure_wire_start(PureWire *w, void (*notify)(void *), void *context) { + w->notify = notify; + w->context = context; + w->started = pthread_create(&w->thread, NULL, deliver, w) == 0; + return w->started; +} + +void pure_wire_close(PureWire *w) { + if (!w) return; + pthread_mutex_lock(&w->lock); + w->stopping = true; + if (w->fd >= 0) shutdown(w->fd, SHUT_RDWR); /* a send or an answer waited for ends now */ + pthread_cond_broadcast(&w->changed); + pthread_mutex_unlock(&w->lock); + if (w->started) pthread_join(w->thread, NULL); + if (w->ssl) SSL_free(w->ssl); + if (w->fd >= 0) close(w->fd); + for (size_t i = 0; i < w->count; ++i) { + free(w->queue[w->head + i].body); + free(w->queue[w->head + i].sent); + } + for (size_t i = 0; i < w->answer_count; ++i) free(w->answers[w->answer_head + i].bytes); + free(w->answers); + free(w->taken.bytes); + free(w->queue); + pthread_cond_destroy(&w->changed); + pthread_mutex_destroy(&w->lock); + free(w); +} |