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// 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;
}
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