From f93f24f3a5ca4692a28ab4970bbf158e1f486074 Mon Sep 17 00:00:00 2001
From: Miguel <m.i@gmx.at>
Date: Tue, 25 Sep 2018 21:46:15 +0200
Subject: pinging fool os works

---
 net/icmp.c | 41 ++++++++++++++++++++++++++++++++++++++---
 net/icmp.h |  2 +-
 net/ipv4.c |  2 +-
 3 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/net/icmp.c b/net/icmp.c
index 038e32a..54dc67b 100644
--- a/net/icmp.c
+++ b/net/icmp.c
@@ -1,20 +1,55 @@
 #include "inet.h"
 #include "icmp.h"
+#include "ipv4.h"
 #include "log.h"
 
-bool icmp_incoming(struct netdev *dev,struct icmp_v4 *data, uint32_t count_bytes)
+#include "lib/string/string.h"
+
+bool icmp_reply(struct netdev *dev,struct eth_hdr *hdr)
+{
+    unsigned char tmp[6];
+    memcpy(tmp,hdr->dmac,6);
+    memcpy(hdr->dmac,hdr->smac,6);
+    memcpy(hdr->smac,tmp,6);
+
+    struct ipv4_hdr *ipv4=hdr->payload;
+
+
+    uint32_t tmp2;
+    tmp2=ipv4->saddr;
+    ipv4->saddr=ipv4->daddr;
+    ipv4->daddr=tmp2;
+    uint32_t daddr;		 // destination ip address
+
+    struct icmp_v4 *data=(uint32_t *)ipv4+ipv4->ihl;
+    data->type=ICMP_ECHO_REPLY;
+    data->csum=0;
+    ipv4->csum=0;
+
+    data->csum=htons(checksum(data,ipv4->len-ipv4->ihl*4));
+    ipv4->csum=htons(checksum(ipv4,ntohs(ipv4->len)));
+
+    dev->transmit(hdr,ntohs(ipv4->len)+14); // 14bytes for link2
+
+    return true;
+}
+
+bool icmp_incoming(struct netdev *dev,struct eth_hdr *hdr)
 {
+    struct ipv4_hdr *ipv4=hdr->payload;
+    struct icmp_v4 *data=(uint32_t *)ipv4+ipv4->ihl;
+
     klog ("icmp type=%d",data->type);
     klog ("icmp code=%d",data->code);
     klog ("icmp csum=0x%04x",ntohs(data->csum));
     data->csum=0;
-    klog("expected checksum = 0x%04X",checksum(data,count_bytes));
+    klog("expected checksum = 0x%04X",checksum(data,ipv4->len-ipv4->ihl*4));
 
     if(data->type==ICMP_ECHO_REQUEST) // echo request
     {
 	struct icmp_v4_echo *echo=data->data;
 	klog ("received echo request id=%d, seq=%d, data=%d ",ntohs(echo->id),ntohs(echo->seq),echo->data);
-//	icmp_reply(); /// TODO watchout that this is the memory managed by the network card we are dealing with!!. fix this later.
+	icmp_reply(dev,hdr); /// TODO watchout that this is the memory managed by the network card we are dealing with!!. fix this later.
     }
 
     return true;
diff --git a/net/icmp.h b/net/icmp.h
index c2c5e8f..50613bb 100644
--- a/net/icmp.h
+++ b/net/icmp.h
@@ -25,4 +25,4 @@ struct icmp_v4_dst_unreachable {
     uint8_t data[];
 } __attribute__((packed));
 
-bool icmp_incoming(struct netdev *dev,struct icmp_v4 *data, uint32_t count_bytes);
+bool icmp_incoming(struct netdev *dev,struct eth_hdr *hdr);
diff --git a/net/ipv4.c b/net/ipv4.c
index aa8502e..b7e6a53 100644
--- a/net/ipv4.c
+++ b/net/ipv4.c
@@ -13,7 +13,7 @@ bool ipv4_incoming(struct netdev *dev,struct eth_hdr *hdr)
     klog("ipv4 header len=%d",ipv4->ihl);
     if(ipv4->proto==IPV4_P_ICMP)
     {
-	icmp_incoming(dev,((uint32_t *)ipv4)+ipv4->ihl,ntohs(ipv4->len)-ipv4->ihl*4);
+	icmp_incoming(dev,hdr);
     }
 
     return true;
-- 
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