Update. I should rethink un-merging that from kernel

Makefile

@@ -20,7 +20,10 @@ STAGE_BIN=$(STAGE)/init \
 		  $(STAGE)/bin/ls \
 		  $(STAGE)/bin/rm \
 		  $(STAGE)/bin/reboot \
-		  $(STAGE)/bin/mkdir
+		  $(STAGE)/bin/mkdir \
+		  $(STAGE)/bin/netctl \
+		  $(STAGE)/bin/netmeow \
+		  $(STAGE)/bin/netdump
 
 #		  $(STAGE)/bin/com \
 #		  $(STAGE)/bin/ase \

core/bin/netctl.c

@@ -0,0 +1,44 @@
+#include <sys/netctl.h>
+#include <errno.h>
+#include <stdio.h>
+
+int main(int argc, char **argv) {
+    if (argc == 2) {
+        uint32_t inaddr;
+
+        if (netctl(argv[1], NETCTL_GET_INADDR, &inaddr) != 0) {
+            if (errno == ENOENT) {
+                printf("No address\n");
+                return 0;
+            }
+            perror("netctl()");
+            return -1;
+        }
+
+        printf("%d.%d.%d.%d\n", inaddr >> 24, (inaddr >> 16) & 0xFF, (inaddr >> 8) & 0xFF, inaddr & 0xFF);
+        return 0;
+    } else if (argc == 3) {
+        uint32_t inaddr_bytes[4];
+
+        if (sscanf(argv[2], "%d.%d.%d.%d", &inaddr_bytes[0], &inaddr_bytes[1], &inaddr_bytes[2], &inaddr_bytes[3]) != 4) {
+            printf("Invalid address format\n");
+            return -1;
+        }
+
+        uint32_t inaddr = (inaddr_bytes[0] & 0xFF) << 24 |
+                          (inaddr_bytes[1] & 0xFF) << 16 |
+                          (inaddr_bytes[2] & 0xFF) << 8 |
+                          (inaddr_bytes[3] & 0xFF);
+
+
+        if (netctl(argv[1], NETCTL_SET_INADDR, &inaddr) != 0) {
+            perror("netctl()");
+            return -1;
+        }
+
+        return 0;
+    } else {
+        printf("Usage: netctl <interface> [<address>]\n");
+        return -1;
+    }
+}

core/bin/netdump.c

@@ -0,0 +1,75 @@
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <stdio.h>
+
+#define LINE_LENGTH         16
+
+static void line_print(size_t off, const char *line, size_t len) {
+    printf("%08x: ", off);
+    for (size_t i = 0; i < LINE_LENGTH; ++i) {
+        // XXX: This is needed because I didn't implement h/hh modifiers in printf
+        uint64_t byte = (uint64_t) line[i] & 0xFF;
+        if (i < len) {
+            printf("%02x", byte);
+        } else {
+            printf("  ");
+        }
+        if (i % 2) {
+            printf(" ");
+        }
+    }
+    printf("| ");
+    for (size_t i = 0; i < len; ++i) {
+        // TODO: isprint?
+        if (((uint8_t) line[i]) >= ' ') {
+            printf("%c", line[i]);
+        } else {
+            printf(".");
+        }
+    }
+    printf("\n");
+}
+
+void packet_dump(const char *buf, size_t len) {
+    char line[LINE_LENGTH];
+    size_t linel = 0;
+    size_t off = 0;
+
+    for (size_t i = 0; i < len; ++i) {
+        line[linel++] = buf[i];
+        if (linel == LINE_LENGTH) {
+            line_print(off, line, linel);
+
+            off += LINE_LENGTH;
+            linel = 0;
+        }
+    }
+    if (linel) {
+        line_print(off, line, linel);
+    }
+}
+
+int main(int argc, char **argv) {
+    struct sockaddr sa;
+    size_t salen;
+    char buf[4096];
+    int fd = socket(AF_PACKET, SOCK_RAW, 0);
+
+    if (fd < 0) {
+        perror("socket()");
+        return -1;
+    }
+
+    while (1) {
+        ssize_t len = recvfrom(fd, buf, sizeof(buf), &sa, &salen);
+
+        if (len < 0) {
+            perror("recvfrom()");
+            break;
+        }
+
+        packet_dump(buf, len);
+    }
+
+    return 0;
+}

core/bin/netmeow.c

@@ -0,0 +1,36 @@
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <stdio.h>
+
+int main(int argc, char **argv) {
+    char buf[4096];
+    struct sockaddr_in sa;
+    int fd = socket(AF_INET, SOCK_DGRAM, 0);
+    size_t salen;
+
+    if (fd < 0) {
+        perror("socket()");
+        return -1;
+    }
+
+    sa.sin_family = AF_INET;
+    sa.sin_port = htons(60);
+    sa.sin_addr = INADDR_ANY;
+
+    if (bind(fd, (struct sockaddr *) &sa, sizeof(struct sockaddr_in)) != 0) {
+        perror("bind()");
+        return -1;
+    }
+
+    while (1) {
+        ssize_t d = recvfrom(fd, buf, sizeof(buf), (struct sockaddr *) &sa, &salen);
+        if (d < 0) {
+            perror("recvfrom()");
+            break;
+        }
+        write(STDOUT_FILENO, buf, d);
+    }
+
+    return 0;
+}

init.c

@@ -1,3 +1,4 @@
+#include <sys/netctl.h>
 #include <sys/mount.h>
 #include <sys/mman.h>
 #include <sys/wait.h>
@@ -26,5 +27,8 @@ int main(int argc, char **argv) {
     mount(NULL, "/sys", "sysfs", 0, NULL);
     mount("/dev/sda1", "/mnt", NULL, 0, NULL);
 
+    uint32_t inaddr = 0x0A000001;
+    netctl("eth0", NETCTL_SET_INADDR, &inaddr);
+
     return start_login();
 }