arp replies working!

1 files changed, 126 insertions, 0 deletions

diff --git a/net/arp.c b/net/arp.c
new file mode 100644
index 0000000..501186f
--- /dev/null
+++ b/net/arp.c
@@ -0,0 +1,126 @@
+// https://github.com/saminiir/level-ip/blob/e9ceb08f01a5499b85f03e2d615309c655b97e8f/src/arp.c#L53
+// https://github.com/chobits/tapip
+// https://tools.ietf.org/html/rfc826
+
+#include "inet.h"
+#include "eth.h"
+#include "arp.h"
+#include "netdev.h"
+#include "log.h"
+
+#include "lib/string/string.h"
+
+/*
+ */
+/*
+static struct arp_cache_entry arp_cache[ARP_CACHE_LEN];
+
+static int insert_arp_translation_table(struct arp_hdr *hdr, struct arp_ipv4 *data)
+{
+    struct arp_cache_entry *entry;
+    for (int i = 0; i<ARP_CACHE_LEN; i++) {
+        entry = &arp_cache[i];
+
+        if (entry->state == ARP_FREE) {
+            entry->state = ARP_RESOLVED;
+
+            entry->hwtype = hdr->hwtype;
+            entry->sip = data->sip;
+            memcpy(entry->smac, data->smac, sizeof(entry->smac));
+
+            return 0;
+        }
+    }
+
+    return -1;
+}
+
+static int update_arp_translation_table(struct arp_hdr *hdr, struct arp_ipv4 *data)
+{
+    struct arp_cache_entry *entry;
+
+    for (int i = 0; i<ARP_CACHE_LEN; i++) {
+        entry = &arp_cache[i];
+
+        if (entry->state == ARP_FREE) continue;
+
+        if (entry->hwtype == hdr->hwtype && entry->sip == data->sip) {
+            memcpy(entry->smac, data->smac, 6);
+            return 1;
+        }
+    }
+    
+    return 0;
+}
+
+void arp_init()
+{
+    memset(arp_cache, 0, ARP_CACHE_LEN * sizeof(struct arp_cache_entry));
+}
+*/
+
+void arp_reply(struct netdev *netdev, struct eth_hdr *hdr, struct arp_hdr *arphdr) 
+{
+    struct arp_ipv4 *arpdata;
+    int len;
+
+    arpdata = (struct arp_ipv4 *) arphdr->data;
+
+    memcpy(arpdata->dmac, arpdata->smac, 6);
+    arpdata->dip = arpdata->sip;
+    memcpy(arpdata->smac, netdev->hwaddr, 6);
+    arpdata->sip = netdev->ip;
+
+    arphdr->opcode = ARP_REPLY;
+
+    arphdr->opcode = htons(arphdr->opcode);
+    arphdr->hwtype = htons(arphdr->hwtype);
+    arphdr->protype = htons(arphdr->protype);
+
+    len = sizeof(struct arp_hdr) + sizeof(struct arp_ipv4);
+    netdev_transmit(netdev, hdr, ETH_P_ARP, len, arpdata->dmac);
+}
+
+void arp_incoming(struct netdev *netdev, struct eth_hdr *hdr)
+{
+    struct arp_hdr *arphdr;
+    struct arp_ipv4 *arpdata;
+    int merge = 0;
+
+    arphdr = (struct arp_hdr *) hdr->payload;
+
+    arphdr->hwtype = ntohs(arphdr->hwtype);
+    arphdr->protype = ntohs(arphdr->protype);
+    arphdr->opcode = ntohs(arphdr->opcode);
+
+    if (arphdr->hwtype != ARP_ETHERNET) {
+        klog("Unsupported HW type\n");
+        return;
+    }
+
+    if (arphdr->protype != ARP_IPV4) {
+        klog("Unsupported protocol\n");
+        return;
+    }
+
+    arpdata = (struct arp_ipv4 *) arphdr->data;
+
+//    merge = update_arp_translation_table(arphdr, arpdata);
+
+    if (netdev->ip != arpdata->dip) {
+        klog("ARP was not for us\n");
+    }
+
+//    if (!merge && insert_arp_translation_table(arphdr, arpdata) != 0) {
+  //     klog("ERR: No free space in ARP translation table\n"); 
+   // }
+
+    switch (arphdr->opcode) {
+    case ARP_REQUEST:
+        arp_reply(netdev, hdr, arphdr);
+        break;
+    default:
+        klog("Opcode not supported\n");
+        break;
+    }
+}