1 files changed, 149 insertions, 0 deletions
diff --git a/v2/server.c b/v2/server.c
new file mode 100644
index 0000000..c86964e
--- /dev/null
+++ b/v2/server.c
@@ -0,0 +1,149 @@
+#include "arena.h"
+#include "common.h"
+
+#include <assert.h>
+#include <netinet/in.h>
+#include <poll.h>
+#include <stdarg.h>
+#include <sys/socket.h>
+
+// timeout on polling
+#define TIMEOUT 60 * 1000
+// max pending connections
+#define PENDING_MAX 16
+
+// the size of pollfd element in the fdsArena
+// note: clientsArena and pollfd_size must have been initialisezd
+#define FDS_SIZE fdsArena->pos / pollfd_size
+
+// enum for indexing the fds array
+enum { FDS_STDIN = 0,
+       FDS_SERVER,
+       FDS_CLIENTS };
+
+int main(void)
+{
+    u32 err, serverfd, clientfd;
+    u16 nclient = 0;
+    u32 on = 1;
+
+    // Start listening on the socket
+    {
+        serverfd = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP);
+        assert(serverfd > 2);
+
+        err = setsockopt(serverfd, SOL_SOCKET, SO_REUSEADDR, (u8 *)&on, sizeof(on));
+        assert(err == 0);
+
+        const struct sockaddr_in address = {
+            AF_INET,
+            htons(PORT),
+            {0},
+        };
+
+        err = bind(serverfd, (const struct sockaddr *)&address, sizeof(address));
+        assert(err == 0);
+
+        err = listen(serverfd, PENDING_MAX);
+        assert(err == 0);
+    }
+
+    Arena *msgTextArena = ArenaAlloc(); // allocating text in messages that have a dynamic sized
+    Message mrecv = {0};                // message used for receiving messages from clients
+    u32 nrecv = 0;                      // number of bytes received
+    u32 nsend = 0;                      // number of bytes sent
+    u8 buf[STREAM_BUF] = {0};           // temporary buffer for received data, NOTE: this buffer
+                                        // is also use for retransmitting received messages to other
+                                        // clients.
+
+    Arena *fdsArena = ArenaAlloc();
+    struct pollfd *fds = fdsArena->memory; // helper for indexing memory
+    struct pollfd c = {0, POLLIN, 0};      // helper client structure fore reusing
+    struct pollfd *fdsAddr;                // used for copying clients
+    const u64 pollfd_size = sizeof(struct pollfd);
+
+    // initialize fds structure
+    // add stdin (c.fd == 0)
+    fdsAddr = ArenaPush(fdsArena, pollfd_size);
+    memcpy(fdsAddr, &c, pollfd_size);
+    // add serverfd
+    c.fd = serverfd;
+    fdsAddr = ArenaPush(fdsArena, pollfd_size);
+    memcpy(fdsAddr, &c, pollfd_size);
+
+    while (1) {
+        err = poll(fds, FDS_SIZE, TIMEOUT);
+        assert(err != -1);
+
+        if (fds[FDS_STDIN].revents & POLLIN) {
+            // helps for testing and exiting gracefully
+            break;
+        } else if (fds[FDS_SERVER].revents & POLLIN) {
+            clientfd = accept(serverfd, NULL, NULL);
+            assert(clientfd != -1);
+            assert(clientfd > serverfd);
+
+            // fill up a hole
+            u8 found = 0;
+            for (u32 i = FDS_CLIENTS; i < FDS_SIZE; i++) {
+                if (fds[i].fd == -1) {
+                    fds[i].fd = clientfd;
+                    // note we do not have to reset .revents because poll will set it to 0 next time
+                    found = 1;
+                    break;
+                }
+            }
+
+            // allocate an extra client because there was no empty spot in the fds array
+            if (!found) {
+                // add client to arena
+                fdsAddr = ArenaPush(fdsArena, pollfd_size);
+                c.fd = clientfd;
+                memcpy(fdsAddr, &c, pollfd_size);
+            }
+
+            nclient++;
+            fprintf(stdout, "connected(%d).\n", clientfd - serverfd);
+        }
+
+        for (u32 i = FDS_CLIENTS; i < (FDS_SIZE); i++) {
+            if (!(fds[i].revents & POLLIN))
+                continue;
+            if (fds[i].fd == -1)
+                continue;
+
+            nrecv = recv(fds[i].fd, buf, STREAM_LIMIT, 0);
+            assert(nrecv >= 0);
+
+            if (nrecv == 0) {
+                fprintf(stdout, "disconnected(%d). \n", fds[i].fd - serverfd);
+                shutdown(fds[i].fd, SHUT_RDWR);
+                close(fds[i].fd); // send close to client
+                fds[i].fd = -1;   // ignore in the future
+                continue;
+            }
+
+            // TODO: Do not print the message in the logs
+            fprintf(stdout, "message(%d): %d bytes.\n", fds[i].fd - serverfd, nrecv); 
+
+            for (u32 j = FDS_CLIENTS; j < (FDS_SIZE); j++) {
+                if (j == i)
+                    continue;
+                if (fds[j].fd == -1)
+                    continue;
+
+                nsend = send(fds[j].fd, buf, nrecv, 0);
+                assert(nsend != 1);
+                assert(nsend == nrecv);
+                fprintf(stdout, "retransmitted(%d->%d).\n", fds[i].fd - serverfd, fds[j].fd - serverfd);
+            }
+
+            ArenaPop(msgTextArena, mrecv.text_len);
+        }
+    }
+
+    ArenaRelease(fdsArena);
+    ArenaRelease(msgTextArena);
+
+    return 0;
+}