Kernel+LibC+Userland: Start working on an IPv4 socket backend.

The first userland networking program will be "ping" :^)

LibC/Makefile

@@ -39,6 +39,7 @@ LIBC_OBJS = \
        sys/wait.o \
        poll.o \
        locale.o \
+       arpa/inet.o \
        crt0.o
 
 ASM_OBJS = setjmp.no

LibC/arpa/inet.cpp

@@ -0,0 +1,19 @@
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <errno.h>
+
+extern "C" {
+
+const char* inet_ntop(int af, const void* src, char* dst, socklen_t len)
+{
+    if (af != AF_INET) {
+        errno = EAFNOSUPPORT;
+        return nullptr;
+    }
+    auto* bytes = (const unsigned char*)src;
+    snprintf(dst, len, "%u.%u.%u.%u", bytes[3], bytes[2], bytes[1], bytes[0]);
+    return (const char*)dst;
+}
+
+}
+

LibC/arpa/inet.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <sys/cdefs.h>
+#include <sys/socket.h>
+
+__BEGIN_DECLS
+
+const char* inet_ntop(int af, const void* src, char* dst, socklen_t);
+
+static inline uint16_t htons(uint16_t hs)
+{
+    uint8_t* s = (uint8_t*)&hs;
+    return (uint16_t)(s[0] << 8 | s[1]);
+}
+
+static inline uint16_t ntohs(uint16_t ns)
+{
+    return htons(ns);
+}
+
+__END_DECLS
+

LibC/netinet/ip_icmp.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <sys/cdefs.h>
+#include <stdint.h>
+
+__BEGIN_DECLS
+
+struct icmphdr {
+    uint8_t type;
+    uint8_t code;
+    uint16_t checksum;
+    union {
+        struct {
+            uint16_t id;
+            uint16_t sequence;
+        } echo;
+        uint32_t gateway;
+    } un;
+};
+
+__END_DECLS
+

LibC/sys/socket.cpp

@@ -34,5 +34,12 @@ int connect(int sockfd, const sockaddr* addr, socklen_t addrlen)
     __RETURN_WITH_ERRNO(rc, rc, -1);
 }
 
+ssize_t sendto(int sockfd, const void* data, size_t data_length, int flags, const struct sockaddr* addr, socklen_t addr_length)
+{
+    Syscall::SC_sendto_params params { sockfd, data, data_length, flags, addr, addr_length };
+    int rc = syscall(SC_sendto, &params);
+    __RETURN_WITH_ERRNO(rc, rc, -1);
+}
+
 }
 

LibC/sys/socket.h

@@ -2,34 +2,55 @@
 
 #include <sys/cdefs.h>
 #include <sys/types.h>
+#include <stdint.h>
 
 __BEGIN_DECLS
 
 #define AF_MASK 0xff
 #define AF_UNSPEC 0
 #define AF_LOCAL 1
+#define AF_INET 2
+#define PF_LOCAL AF_LOCAL
+#define PF_INET AF_INET
 
 #define SOCK_TYPE_MASK 0xff
 #define SOCK_STREAM 1
+#define SOCK_RAW 3
 #define SOCK_NONBLOCK 04000
 #define SOCK_CLOEXEC 02000000
 
+#define IPPROTO_ICMP 1
+#define IPPROTO_TCP 6
+#define IPPROTO_UDP 17
+
 struct sockaddr {
-    unsigned short sa_family;
+    uint16_t sa_family;
     char sa_data[14];
 };
 
 #define UNIX_PATH_MAX 108
 struct sockaddr_un {
-    unsigned short sun_family;
+    uint16_t sun_family;
     char sun_path[UNIX_PATH_MAX];
 };
 
+struct in_addr {
+    uint32_t s_addr;
+};
+
+struct sockaddr_in {
+    uint16_t sin_family;
+    uint16_t sin_port;
+    struct in_addr sin_addr;
+    char sin_zero[8];
+};
+
 int socket(int domain, int type, int protocol);
 int bind(int sockfd, const sockaddr* addr, socklen_t);
 int listen(int sockfd, int backlog);
 int accept(int sockfd, sockaddr*, socklen_t*);
 int connect(int sockfd, const sockaddr*, socklen_t);
+ssize_t sendto(int sockfd, const void*, size_t, int flags, const struct sockaddr*, socklen_t);
 
 __END_DECLS