Kernel: Expose source information of incoming UDP packets

1 files changed, 35 insertions, 12 deletions

diff --git a/network/udp.c b/network/udp.c
index fb8ba44..29f17e1 100644
--- a/network/udp.c
+++ b/network/udp.c
@@ -3,24 +3,47 @@
 #include <network/udp.h>
 #include <socket.h>
 
-void handle_udp(const uint8_t *payload, uint32_t packet_length) {
+void handle_udp(uint8_t src_ip[4], const uint8_t *payload,
+                uint32_t packet_length) {
   assert(packet_length >= 8);
-  uint16_t source_port = ntohs(*(uint16_t *)payload);
-  uint16_t dst_port = ntohs(*(uint16_t *)(payload + 2));
-  uint16_t length = ntohs(*(uint16_t *)(payload + 4));
-  assert(length == packet_length);
-  kprintf("source_port: %d\n", source_port);
-  kprintf("dst_port: %d\n", dst_port);
-  uint32_t data_length = length - 8;
+  // n_.* means network format(big endian)
+  // h_.* means host format((probably) little endian)
+  uint16_t n_source_port = *(uint16_t *)payload;
+  uint16_t h_source_port = ntohs(n_source_port);
+  uint16_t h_dst_port = ntohs(*(uint16_t *)(payload + 2));
+  uint16_t h_length = ntohs(*(uint16_t *)(payload + 4));
+  assert(h_length == packet_length);
+  kprintf("source_port: %d\n", h_source_port);
+  kprintf("dst_port: %d\n", h_dst_port);
+  uint16_t data_length = h_length - 8;
   const uint8_t *data = payload + 8;
 
   // Find the open port
-  OPEN_INET_SOCKET *in_s = find_open_udp_port(htons(dst_port));
+  OPEN_INET_SOCKET *in_s = find_open_udp_port(htons(h_dst_port));
   assert(in_s);
   SOCKET *s = in_s->s;
   vfs_fd_t *fifo_file = s->ptr_socket_fd;
+
+  // Write the sockaddr struct such that it can later be
+  // given to userland if asked.
+  struct sockaddr_in /*{
+    sa_family_t sin_family;
+    union {
+      uint32_t s_addr;
+    } sin_addr;
+    uint16_t sin_port;
+  }*/ in;
+  in.sin_family = AF_INET;
+  memcpy(&in.sin_addr.s_addr, src_ip, sizeof(uint32_t));
+  in.sin_port = n_source_port;
+  socklen_t sock_length = sizeof(struct sockaddr_in);
+
+  raw_vfs_pwrite(fifo_file, &sock_length, sizeof(sock_length), 0);
+  raw_vfs_pwrite(fifo_file, &in, sizeof(in), 0);
+
+  // Write the UDP payload length(not including header)
+  raw_vfs_pwrite(fifo_file, &data_length, sizeof(uint16_t), 0);
+
+  // Write the UDP payload
   raw_vfs_pwrite(fifo_file, (char *)data, data_length, 0);
-  for (uint32_t i = 0; i < data_length; i++) {
-    kprintf("%c", data[i]);
-  }
 }