Files
zern/src/std/net.zr
2026-03-14 13:10:26 +01:00

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const AF_INET = 2
const SOCK_STREAM = 1
const SOCK_DGRAM = 2
const SOL_SOCKET = 1
const SO_REUSEADDR = 2
func net.listen[packed_host: i64, port: i64] : i64
let s: i64 = _builtin_syscall(SYS_socket, AF_INET, SOCK_STREAM, 0)
if s < 0
return -1
let optval = 1
if _builtin_syscall(SYS_setsockopt, s, SOL_SOCKET, SO_REUSEADDR, ^optval, 8) < 0
_builtin_syscall(SYS_close, s)
return -1
let sa: ptr = mem.alloc(16)
mem.zero(sa, 16)
sa[0] = 2
sa[1] = 0
sa[2] = (port >> 8) & 255
sa[3] = port & 255
sa[4] = (packed_host >> 24) & 255
sa[5] = (packed_host >> 16) & 255
sa[6] = (packed_host >> 8) & 255
sa[7] = packed_host & 255
if _builtin_syscall(SYS_bind, s, sa, 16) < 0
_builtin_syscall(SYS_close, s)
mem.free(sa)
return -1
mem.free(sa)
if _builtin_syscall(SYS_listen, s, 128) < 0
_builtin_syscall(SYS_close, s)
return -1
return s
// TODO: resolve DNS
func net.connect[packed_host: i64, port: i64] : i64
let s: i64 = _builtin_syscall(SYS_socket, AF_INET, SOCK_STREAM, 0)
if s < 0
return -1
let sa: ptr = mem.alloc(16)
mem.zero(sa, 16)
sa[0] = AF_INET
sa[1] = 0
sa[2] = (port >> 8) & 255
sa[3] = port & 255
sa[4] = (packed_host >> 24) & 255
sa[5] = (packed_host >> 16) & 255
sa[6] = (packed_host >> 8) & 255
sa[7] = packed_host & 255
if _builtin_syscall(SYS_connect, s, sa, 16) < 0
mem.free(sa)
_builtin_syscall(SYS_close, s)
return -1
mem.free(sa)
return s
func net.accept[s: i64] : i64
return _builtin_syscall(SYS_accept, s, 0, 0)
func net.send[s: i64, data: ptr, size: i64] : void
_builtin_syscall(SYS_sendto, s, data, size, 0, 0, 0)
func net.read[s: i64, buffer: ptr, size: i64] : i64
return _builtin_syscall(SYS_read, s, buffer, size)
func net.close[s: i64] : void
_builtin_syscall(SYS_close, s)
func net.pack_addr[a: i64, b: i64, c: i64, d: i64] : i64
return (a << 24) | (b << 16) | (c << 8) | d
struct net.UDPSocket
fd: i64
addr: ptr
struct net.UDPPacket
data: ptr
source_addr: ptr
size: i64
func net.create_udp_client[packed_host: i64, port: i64] : net.UDPSocket
let s: net.UDPSocket = new net.UDPSocket
s->fd = _builtin_syscall(SYS_socket, AF_INET, SOCK_DGRAM, 0)
if s->fd < 0
mem.free(s)
return 0
s->addr = mem.alloc(16)
mem.zero(s->addr, 16)
s->addr[0] = AF_INET
s->addr[1] = 0
s->addr[2] = (port >> 8) & 255
s->addr[3] = port & 255
s->addr[4] = (packed_host >> 24) & 255
s->addr[5] = (packed_host >> 16) & 255
s->addr[6] = (packed_host >> 8) & 255
s->addr[7] = packed_host & 255
return s
func net.udp_listen[packed_host: i64, port: i64] : net.UDPSocket
let s: net.UDPSocket = net.create_udp_client(packed_host, port)
if !s
return 0
if _builtin_syscall(SYS_bind, s->fd, s->addr, 16) < 0
net.UDPSocket.close_and_free(s)
return 0
return s
func net.udp_send_to[s: net.UDPSocket, addr: ptr, data: ptr, size: i64] : void
_builtin_syscall(SYS_sendto, s->fd, data, size, 0, addr, 16)
func net.udp_receive[s: net.UDPSocket, size: i64] : net.UDPPacket
let pkt: net.UDPPacket = new net.UDPPacket
pkt->data = mem.alloc(size)
pkt->source_addr = mem.alloc(16)
mem.zero(pkt->source_addr, 16)
let addrlen: i64 = 16
pkt->size = _builtin_syscall(SYS_recvfrom, s->fd, pkt->data, size, 0, pkt->source_addr, ^addrlen)
return pkt
func net.UDPSocket.close_and_free[s: net.UDPSocket] : void
_builtin_syscall(SYS_close, s->fd)
mem.free(s->addr)
mem.free(s)
func net.UDPPacket.free[pkt: net.UDPPacket] : void
mem.free(pkt->data)
mem.free(pkt->source_addr)
mem.free(pkt)
const DNS_TYPE_A = 1
const DNS_CLASS_IN = 1
const DNS_RECURSION_DESIRED = 256
func net.encode_dns_name[domain: str] : io.Buffer
let domain_len: i64 = str.len(domain)
let buf: io.Buffer = io.Buffer.alloc(domain_len + 2)
let out_pos: i64 = 0
let part_start: i64 = 0
let i: i64 = 0
while i <= domain_len
if i == domain_len || domain[i] == '.'
let part_len: i64 = i - part_start
buf->data[out_pos] = part_len & 0xff
out_pos = out_pos + 1
mem.copy(domain + part_start, buf->data + out_pos, part_len)
out_pos = out_pos + part_len
part_start = i + 1
i = i + 1
buf->data[out_pos] = 0
return buf
func net.build_dns_query[domain_name: str, record_type: i64] : io.Buffer
let name: io.Buffer = net.encode_dns_name(domain_name)
let out: io.Buffer = io.Buffer.alloc(12 + name->size + 4)
// header
let id: i64 = math.abs(os.urandom_i64() % 65536)
mem.write16be(out->data + 0, id)
mem.write16be(out->data + 2, DNS_RECURSION_DESIRED)
mem.write16be(out->data + 4, 1) // num_questions
mem.write16be(out->data + 6, 0) // num_answers
mem.write16be(out->data + 8, 0) // num_authorities
mem.write16be(out->data + 10, 0) // num_additionals
// question
mem.copy(name->data, out->data + 12, name->size)
mem.write16be(out->data + 12 + name->size, record_type)
mem.write16be(out->data + 12 + name->size + 2, DNS_CLASS_IN)
io.Buffer.free(name)
return out
func net.resolve[domain: str] : i64
let query: io.Buffer = net.build_dns_query(domain, DNS_TYPE_A)
// TODO: this probably shouldnt be hardcoded
let s: net.UDPSocket = net.create_udp_client(net.pack_addr(8, 8, 8, 8), 53)
if s == 0
return 0
net.udp_send_to(s, s->addr, query->data, query->size)
io.Buffer.free(query)
let pkt: net.UDPPacket = net.udp_receive(s, 1024)
net.UDPSocket.close_and_free(s)
// TODO: do actual parsing
let pos: i64 = 12 // skip header (12 bytes)
while pkt->data[pos] != 0
pos = pos + pkt->data[pos] + 1 // skip question
pos = pos + 5 // skip null byte, type(2), class(2)
pos = pos + 12 // skip name(2), type(2), class(2), ttl(4), rdlength(2)
let out: i64 = net.pack_addr(pkt->data[pos], pkt->data[pos+1], pkt->data[pos+2], pkt->data[pos+3])
net.UDPPacket.free(pkt)
return out