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LookupServer+LibC: Pass IP addresses in binary

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Now that we no longer depend on the textual IPC format, we can pass IP addresses
in the format most code actually has and needs it: in binary. The only places we
actually have to deal with textual address representation is:

* When reading /etc/hosts, we have to parse textual addresses & convert them to
  binary;
* When doing reverse lookups, we have to form a pseudo-hostname of the form
  x.x.x.x.in-addr.arpa.

So we do the conversion in those two cases.

This also increases uniformity between how we handle A (IPv4 address) and other
resource record types. Namely, we now store the raw binary data as received from
a DNS server.
This commit is contained in:
Sergey Bugaev 2021-02-06 17:30:33 +03:00 • committed by Andreas Kling
parent 04ff46bff4
commit d8967e4dff
4 changed files with 12 additions and 19 deletions
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20
Userland/Libraries/LibC/netdb.cpp
View file

@ -181,19 +181,14 @@ hostent* gethostbyname(const char* name)
return nullptr;
}
ASSERT((size_t)nrecv == sizeof(response_length));
ASSERT(response_length == sizeof(__gethostbyname_address));
char response[response_length + 1];
nrecv = read(fd, response, response_length);
nrecv = read(fd, &__gethostbyname_address, response_length);
if (nrecv < 0) {
perror("recv");
return nullptr;
}
ASSERT(nrecv == response_length);
response[response_length] = 0;
int rc = inet_pton(AF_INET, response, &__gethostbyname_address);
if (rc <= 0)
return nullptr;
gethostbyname_name_buffer = name;
__gethostbyname_buffer.h_name = const_cast<char*>(gethostbyname_name_buffer.characters());
@ -230,8 +225,7 @@ hostent* gethostbyaddr(const void* addr, socklen_t addr_size, int type)
close(fd);
});
IPv4Address ipv4_address((const u8*)&((const in_addr*)addr)->s_addr);
auto address = ipv4_address.to_string();
const in_addr_t& in_addr = ((const struct in_addr*)addr)->s_addr;
struct [[gnu::packed]] {
u32 message_size;
@ -239,10 +233,10 @@ hostent* gethostbyaddr(const void* addr, socklen_t addr_size, int type)
i32 message_id;
i32 address_length;
} request_header = {
sizeof(request_header) - sizeof(request_header.message_size) + address.length(),
sizeof(request_header) - sizeof(request_header.message_size) + sizeof(in_addr),
lookup_server_endpoint_magic,
3,
(i32)address.length(),
(i32)sizeof(in_addr),
};
int nsent = write(fd, &request_header, sizeof(request_header));
if (nsent < 0) {
@ -250,12 +244,12 @@ hostent* gethostbyaddr(const void* addr, socklen_t addr_size, int type)
return nullptr;
}
ASSERT((size_t)nsent == sizeof(request_header));
nsent = write(fd, address.characters(), address.length());
nsent = write(fd, &in_addr, sizeof(in_addr));
if (nsent < 0) {
perror("write");
return nullptr;
}
ASSERT((size_t)nsent == address.length());
ASSERT((size_t)nsent == sizeof(in_addr));
struct [[gnu::packed]] {
u32 message_size;