diff options
Diffstat (limited to 'src/net.c')
| -rw-r--r-- | src/net.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/src/net.c b/src/net.c new file mode 100644 index 0000000..18970c1 --- /dev/null +++ b/src/net.c @@ -0,0 +1,231 @@ +// SPDX-FileCopyrightText: 2024 Lizzy Fleckenstein <lizzy@vlhl.dev> +// +// SPDX-License-Identifier: AGPL-3.0-or-later + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <poll.h> +#include <errno.h> +#include <netdb.h> +#include <sys/types.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <arpa/inet.h> + +#include "net.h" + +void invalid_pkt(str from, str pkt) +{ + // TODO: maybe inform peer about failure? not sure + // FIXME: hexdumping a gazillon bytes to stderr might be an issue + fprintf(stderr, "invalid pkt from %*s: ", PSTR(from)); + for (size_t i = 0; i < pkt.len; i++) + fprintf(stderr, "%02x%c", (uint8_t) pkt.data[i], i+1 == pkt.len ? '\n' : ' '); +} + +int socket_create(const char *host, const char *port, bool server) +{ + struct addrinfo *info = NULL, hints = {0}; + hints.ai_family = AF_UNSPEC; + hints.ai_socktype = SOCK_STREAM; + + int err; + if ((err = getaddrinfo(host, port, &hints, &info))) { + fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(err)); + return -1; + } + +#define TRY(op, val) if ((val) < 0) { perror(op); close(fd); freeaddrinfo(info); return -1; } + + int fd = -1; + TRY("socket", fd = socket(info->ai_family, info->ai_socktype, info->ai_protocol)) + + int flag = 1; + TRY("setsockopt", setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (void *) &flag, sizeof flag)) + + if (server) { + TRY("bind", bind(fd, info->ai_addr, info->ai_addrlen)) + TRY("listen", listen(fd, 3)) + } else { + TRY("connect", connect(fd, info->ai_addr, info->ai_addrlen)) + TRY("fcntl", SET_NONBLOCK(fd)) + } + +#undef TRY + + freeaddrinfo(info); + return fd; +} + +int socket_accept(int accept_fd) +{ + int socket = accept(accept_fd, NULL, NULL); // TODO: save address + if (socket < 0) { + perror("accept"); + return -1; + } + + if (SET_NONBLOCK(socket) < 0) { + perror("fcntl"); + close(socket); + return -1; + } + + return socket; +} + +void peer_init(peer *p, int socket) +{ + p->socket = socket; + p->disco = false; + + p->in.header = true; + p->in.len = 0; + p->in.promised = 0; + p->in.buffer = malloc(PEER_INBUFFER_SIZE); + + p->out.cursor = 0; + p->out.avail = 0; + p->out.buffer = malloc(PEER_OUTBUFFER_SIZE); +} + +void peer_free(peer *p) +{ + close(p->socket); + free(p->in.buffer); + free(p->out.buffer); +} + +// in + +static void next_in(peer *p, bool header, size_t len) +{ + p->in.header = header; + p->in.len = 0; + p->in.buffer = malloc(p->in.promised = len); +} + +static bool peer_in_ready(peer *p) +{ + errno = 0; + ssize_t got = read(p->socket, p->in.buffer + p->in.len, p->in.promised - p->in.len); + if (got <= 0) { + switch (errno) { + case 0: case ECONNRESET: + p->disco = true; + return true; + case EINTR: + return peer_in_ready(p); // retry + default: + perror("read"); + return false; + } + } + + p->in.len += got; + if (p->in.len == p->in.promised && p->in.len != 0) { + if (!p->in.header) + return true; + + size_t len = *(pkt_header *) p->in.buffer; + if (len > PEER_INBUFFER_SIZE || len == 0) + // TODO: figure out what to do if packet too large (disconnect?) + next_in(p, true, sizeof(pkt_header)); + else + next_in(p, false, len); + } + + return false; +} + +// out + +static void send_raw(peer *p, void *data, size_t len) +{ + memcpy(p->out.buffer + p->out.cursor + p->out.avail, data, len); + p->out.avail += len; +} + +static bool out_space(peer *p, size_t len) +{ + if (len + p->out.avail > PEER_OUTBUFFER_SIZE) + return false; + + if (p->out.cursor + p->out.avail + len > PEER_OUTBUFFER_SIZE) { + memmove(p->out.buffer, p->out.buffer + p->out.cursor, p->out.avail); + p->out.cursor = 0; + } + + return true; +} + +bool peer_send(peer *p, void *data, size_t len) +{ + if (len > PEER_INBUFFER_SIZE) + return false; + + pkt_header hdr = (pkt_header) len; + + if (!out_space(p, sizeof hdr + len)) + return false; + + send_raw(p, &hdr, sizeof hdr); + send_raw(p, data, len); + + return true; +} + +static bool peer_out_ready(peer *p) +{ + ssize_t written = write(p->socket, p->out.buffer + p->out.cursor, p->out.avail); + if (written < 0) { + switch (errno) { + case ECONNRESET: + p->disco = true; + return true; + case EINTR: + return peer_out_ready(p); + default: + perror("write"); + return false; + } + } + + p->out.avail -= written; + if (p->out.avail == 0) + p->out.cursor = 0; + + return false; +} + +// poll + +struct pollfd peer_prepare(peer *p) +{ + struct pollfd pfd = {0}; + + pfd.fd = p->socket; + if (p->in.len == p->in.promised) + next_in(p, true, sizeof(pkt_header)); + + pfd.events = POLLIN | (p->out.avail ? POLLOUT : 0); + + return pfd; +} + +str peer_recv(peer *p, struct pollfd pfd) +{ + if (pfd.revents & (POLLHUP | POLLERR)) + p->disco = true; + + if (!p->disco && pfd.revents & POLLOUT) + peer_out_ready(p); + + if (!p->disco && pfd.revents & POLLIN) + if (peer_in_ready(p)) + return (str) { p->in.len, (char *) p->in.buffer }; + + return NILS; +} |