formatting & readmes

Makefile

@@ -1,3 +1,6 @@
+# This was my first time writing a makefile so this is likely badly written.
+# Guide: https://www.cs.colostate.edu/~cs157/LectureMakefile.pdf
+
 # Compiler
 CC := gcc
 

include/arp.h

@@ -1,11 +1,11 @@
 #ifndef ARP_H_
 #define ARP_H_
 
-#include "syshead.h"
-#include "skbuff.h"
-#include "eth.h"
 #include "dl_list.h"
+#include "eth.h"
 #include "net_dir.h"
+#include "skbuff.h"
+#include "syshead.h"
 
 // https://datatracker.ietf.org/doc/html/rfc826#autoid-1
 // https://en.wikipedia.org/wiki/Address_Resolution_Protocol#Packet_structure
@@ -19,7 +19,7 @@ struct ipv4_over_eth_arp_pkt {
     uint32_t SPA;
     uint8_t THA[6];
     uint32_t TPA;
-} __attribute__ ((packed));
+} __attribute__((packed));
 
 // https://www.auvik.com/franklyit/blog/what-is-an-arp-table/
 // only implementing the stuff under ARP entry
@@ -36,6 +36,6 @@ struct arp_table_entry {
 void arp_receive(struct sk_buff *skb, struct eth_self_properties *dev);
 void arp_reply(struct sk_buff *skb, struct eth_self_properties *dev, struct ipv4_over_eth_arp_pkt *arp_pkt);
 void arp_request(uint32_t TPA, struct eth_self_properties *dev);
-uint8_t* arp_table_lookup(uint32_t proto_addr);
+uint8_t *arp_table_lookup(uint32_t proto_addr);
 
 #endif

include/dl_list.h

@@ -26,41 +26,46 @@ struct list_head {
 // define all static inline functions in the header file:
 // https://stackoverflow.com/questions/5526461/gcc-warning-function-used-but-not-defined
 
-static inline void list_init(struct list_head *head) {
-  head->next = head;
-  head->prev = head;
+static inline void list_init(struct list_head *head)
+{
+    head->next = head;
+    head->prev = head;
 }
 
-static inline void add_first(struct list_head *new_element, struct list_head *head) {
-  new_element->next = head->next;
-  new_element->prev = head;
-  head->next->prev = new_element;
-  head->next = new_element;
+static inline void add_first(struct list_head *new_element, struct list_head *head)
+{
+    new_element->next = head->next;
+    new_element->prev = head;
+    head->next->prev = new_element;
+    head->next = new_element;
 }
 
-static inline void add_last(struct list_head *new_element, struct list_head *head) {
-  new_element->next = head;
-  new_element->prev = head->prev;
-  head->prev->next = new_element;
-  head->prev = new_element;
+static inline void add_last(struct list_head *new_element, struct list_head *head)
+{
+    new_element->next = head;
+    new_element->prev = head->prev;
+    head->prev->next = new_element;
+    head->prev = new_element;
 }
 
-static inline void remove_elem(struct list_head *elem_to_remove) {
-  elem_to_remove->prev->next = elem_to_remove->next;
-  elem_to_remove->next->prev = elem_to_remove->prev;
+static inline void remove_elem(struct list_head *elem_to_remove)
+{
+    elem_to_remove->prev->next = elem_to_remove->next;
+    elem_to_remove->next->prev = elem_to_remove->prev;
 }
 
-static inline int is_list_empty(struct list_head *head) {
-  return head->next == head;
+static inline int is_list_empty(struct list_head *head)
+{
+    return head->next == head;
 }
 
 #define get_list_item(ptr, type, member) \
-  ((type *)((char *)(ptr) - offsetof(type, member)))
+    ((type *)((char *)(ptr) - offsetof(type, member)))
 
 #define get_list_first_entry(ptr, type, member) \
-  get_list_item((ptr)->next, type, member)
+    get_list_item((ptr)->next, type, member)
 
 #define list_for_each(pos, head) \
-  for (pos = (head)->next; pos != (head); pos = pos->next)
+    for (pos = (head)->next; pos != (head); pos = pos->next)
 
 #endif

include/eth.h

@@ -23,8 +23,8 @@ Linux provides a struct for the ethernet frame header as a guide also:
 #ifndef ETH_H_
 #define ETH_H_
 
-#include "syshead.h"
 #include "skbuff.h"
+#include "syshead.h"
 
 #define ETH_ALEN 6
 
@@ -33,15 +33,14 @@ struct eth_hdr {
     uint8_t ether_shost[ETH_ALEN]; // source mac
     uint16_t ether_type;
     // uint8_t payload[]; // not in official implementation
-} __attribute__ ((packed));
+} __attribute__((packed));
 
-
-static inline struct eth_hdr *unpack_eth_hdr(struct sk_buff *skb) {
+static inline struct eth_hdr *unpack_eth_hdr(struct sk_buff *skb)
+{
     struct eth_hdr *eth_hdr = (struct eth_hdr *)(skb->head);
     // convert ether_type from big endian -> small endian
     eth_hdr->ether_type = ntohs(eth_hdr->ether_type);
     return eth_hdr;
 };
 
-
 #endif

include/icmp.h

@@ -1,8 +1,8 @@
 #ifndef ICMP_H_
 #define ICMP_H_
 
-#include "syshead.h"
 #include "skbuff.h"
+#include "syshead.h"
 
 #define ICMP_TYPE_DEST_UNREACHABLE 0x03
 #define ICMP_TYPE_ECHO 0x08
@@ -14,14 +14,14 @@ struct icmp_base_hdr {
     uint8_t code;
     uint16_t checksum;
     uint8_t data[];
-} __attribute__ ((packed));
+} __attribute__((packed));
 
 // additional data for echos
 struct icmp_echo_additions {
     uint16_t id;
     uint16_t seq_num;
     uint8_t data[];
-} __attribute__ ((packed));
+} __attribute__((packed));
 
 void icmp_receive(struct sk_buff *skb);
 void icmp_reply(struct sk_buff *skb);

include/ip.h

@@ -1,8 +1,8 @@
 #ifndef IP_H_
 #define IP_H_
 
-#include "syshead.h"
 #include "skbuff.h"
+#include "syshead.h"
 #include "tcp_sockets.h"
 
 #define IPV4 0x04 // for ip version in ip_hdr
@@ -13,7 +13,7 @@
 
 struct ip_hdr {
     // https://stackoverflow.com/questions/11197931/what-is-meaning-of-in-struct-c
-    uint8_t IHL : 4; // internet header length
+    uint8_t IHL : 4;     // internet header length
     uint8_t version : 4; // "but how can i get a 4-bit variable?" -- "Build your own microprocessor." - but u can pack bits (see above), though upper bit comes first so IHL & version is reversed
     uint8_t tos;
     uint16_t len;
@@ -27,7 +27,7 @@ struct ip_hdr {
     uint32_t src_addr;
     uint32_t dest_addr;
     uint8_t data[];
-} __attribute__ ((packed));
+} __attribute__((packed));
 
 void ip_rcv(struct sk_buff *skb);
 int ip_transmit(struct tcp_sockets *sock, struct sk_buff *skb);

include/net_dir.h

@@ -1,27 +1,27 @@
 #ifndef NET_DIR_H_
 #define NET_DIR_H_
 
-#include "syshead.h"
 #include "skbuff.h"
+#include "syshead.h"
 
 // our device's properties
 struct eth_self_properties {
-  // fields here are selected from RFC 826's packet reception algo
-  // https://datatracker.ietf.org/doc/html/rfc826#autoid-1 
-  // Naming convention from:
-  // https://en.wikipedia.org/wiki/Address_Resolution_Protocol#Operating_scope
-  // stored in little endian
-  // sidenote: avoid u_int16_t to prevent suicide by coworker
-                   // https://stackoverflow.com/a/23291438/9108905
-  uint16_t PTYPE; // so far we support ipv4 only
-  uint32_t PROTOCOL_ADDR; // we've put 2 x 2 bytes together
-  uint8_t HARDWARE_ADDR[6]; // xx:xx:xx:xx:xx:xx
-  uint32_t mtu;
+    // fields here are selected from RFC 826's packet reception algo
+    // https://datatracker.ietf.org/doc/html/rfc826#autoid-1
+    // Naming convention from:
+    // https://en.wikipedia.org/wiki/Address_Resolution_Protocol#Operating_scope
+    // stored in little endian
+    // sidenote: avoid u_int16_t to prevent suicide by coworker
+    // https://stackoverflow.com/a/23291438/9108905
+    uint16_t PTYPE;           // so far we support ipv4 only
+    uint32_t PROTOCOL_ADDR;   // we've put 2 x 2 bytes together
+    uint8_t HARDWARE_ADDR[6]; // xx:xx:xx:xx:xx:xx
+    uint32_t mtu;
 };
 
-struct eth_self_properties* init_eth_self(char* self_hardware_mac, char* self_protocol_ip,
-                   int self_mtu);
-// TODO: FIX: 
+struct eth_self_properties *init_eth_self(char *self_hardware_mac, char *self_protocol_ip,
+                                          int self_mtu);
+// TODO: FIX:
 // for some stupid reason uncommenting this leads to a conflicting types err, however not including it in header works
 int net_dir_transmit(struct sk_buff *skb, uint8_t *ether_dhost, uint16_t ether_type);
 void net_dir_receive(struct eth_self_properties *dev);

include/route.h

@@ -1,9 +1,9 @@
 #ifndef ROUTE_H_
 #define ROUTE_H_
 
-#include "syshead.h"
-#include "net_dir.h"
 #include "dl_list.h"
+#include "net_dir.h"
+#include "syshead.h"
 
 #define RT_GATEWAY 0x02
 #define RT_HOST 0x04
@@ -19,8 +19,7 @@ struct routing_table_entry {
     struct eth_self_properties *dev; // to store information for lower level network stack - upon correct routing, use info held here for sending
 };
 
-void rt_init(char* gateway_addr, struct eth_self_properties *dev);
+void rt_init(char *gateway_addr, struct eth_self_properties *dev);
 struct routing_table_entry *rt_lookup(uint32_t dest_addr);
 
-
 #endif

include/skbuff.h

@@ -8,8 +8,8 @@ what we need in our skbuff is documented here:
 #define SK_BUFF_H_
 
 #include "dl_list.h"
-#include "route.h"
 #include "net_dir.h"
+#include "route.h"
 #include <pthread.h>
 #include <stdint.h>
 
@@ -19,7 +19,7 @@ struct sk_buff {
     struct eth_self_properties *dev;
     uint32_t interface;
     uint16_t protocol; // 2 byte identifier
-    uint32_t len; // length of packet
+    uint32_t len;      // length of packet
     uint8_t *head;
     uint8_t *data;
     uint8_t *tail;

include/syshead.h

@@ -8,6 +8,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <linux/if.h>
+#include <linux/if_ether.h>
 #include <linux/if_tun.h>
 #include <linux/types.h>
 #include <netdb.h>
@@ -29,10 +30,5 @@
 #include <sys/un.h>
 #include <time.h>
 #include <unistd.h>
-#include <linux/if_ether.h>
 
 #endif
-
-
-
-

include/tcp.h

@@ -1,27 +1,27 @@
-#include "syshead.h"
 #include "skbuff.h"
+#include "syshead.h"
 
 // see rfc 793
 struct tcp_hdr {
     uint16_t src_port;
     uint16_t dest_port;
     uint32_t seq_num;
     uint32_t ack_num;
-    uint8_t reserved: 4;
-    uint8_t data_offset: 4;
-    uint8_t fin: 1,
-            syn: 1,
-            rst: 1,
-            psh: 1,
-            ack: 1,
-            urg: 1,
-            rsv1: 1, // no congestion implementation - https://www.johnpfernandes.com/2018/12/17/tcp-flags-what-they-mean-and-how-they-help/
-            rsv0: 1;
+    uint8_t reserved : 4;
+    uint8_t data_offset : 4;
+    uint8_t fin : 1,
+        syn : 1,
+        rst : 1,
+        psh : 1,
+        ack : 1,
+        urg : 1,
+        rsv1 : 1, // no congestion implementation - https://www.johnpfernandes.com/2018/12/17/tcp-flags-what-they-mean-and-how-they-help/
+        rsv0 : 1;
     uint16_t window;
     uint16_t checksum;
     uint16_t urgent_ptr;
     uint8_t data[];
-} __attribute__ ((packed));
+} __attribute__((packed));
 
 // for tcp checksum
 struct tcp_pseudo_header {
@@ -30,7 +30,6 @@ struct tcp_pseudo_header {
     uint8_t zero;
     uint8_t protocol;
     uint16_t tcp_len;
-} __attribute__ ((packed));
-
+} __attribute__((packed));
 
 void tcp_incoming(struct sk_buff *skb);