feature: parsing with getopt pretty much done (some checks tbd)

include/parsing.h

@@ -0,0 +1,20 @@
+#pragma once
+
+#define NB_OPTIONS 5
+
+typedef enum {
+	FL_HELP,
+	FL_PORTS,
+	FL_IP,
+	FL_SPEEDUP,
+	FL_SCAN,
+} e_flag;
+
+struct option_lst {
+	e_flag flag;
+	char *arg;
+	struct option_lst *next;
+};
+
+struct option_lst *parse_options(int ac, char *const *av);
+char *get_option_arg(struct option_lst *options, e_flag flag);

src/dns.c

@@ -10,7 +10,8 @@ int dns_lookup(char *ip_addr, char *hostname, struct sockaddr_in *addr_con)
 {
 	struct hostent *host = gethostbyname2(hostname, AF_INET);
 	if (!host) {
-		dprintf(2, "Hostname %s doesn't exist or has invalid format.\n",
+		dprintf(2,
+		        "Hostname '%s' doesn't exist or has invalid format.\n",
 		        hostname);
 		return -1;
 	}

src/main.c

@@ -1,3 +1,4 @@
+#include <getopt.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
 #include <pcap.h>
@@ -7,6 +8,7 @@
 
 #include "dns.h"
 #include "interface.h"
+#include "parsing.h"
 #include "print.h"
 #include "scan.h"
 #include "thread.h"
@@ -19,14 +21,22 @@ int main(int ac, char **av)
 		print_usage();
 		return 0;
 	}
-	// TODO parse arguments
-	(void)av;
+
+	struct option_lst *options = parse_options(ac, av);
+	if (options == NULL)
+		return 1;
 
 	char ip_addr[INET_ADDRSTRLEN];
 	struct sockaddr_in addr_con;
-	if (dns_lookup(ip_addr, av[1], &addr_con)) {
-		dprintf(2, "ft_nmap: failed to retrieve ip address from %s\n",
-		        av[1]);
+
+	char *host = get_option_arg(options, FL_IP);
+	if (!host) {
+		dprintf(2, "ft_nmap: address/hostname required\n");
+		return 1;
+	}
+	if (dns_lookup(ip_addr, host, &addr_con)) {
+		dprintf(2, "ft_nmap: failed to retrieve ip address from '%s'\n",
+		        host);
 		return 1;
 	}
 
@@ -45,5 +55,9 @@ int main(int ac, char **av)
 		return 1;
 	}
 
+	int threads_running = 0;
+	while (threads_running)
+		;
+
 	return 0;
 }

src/parsing.c

@@ -0,0 +1,71 @@
+#include <getopt.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "parsing.h"
+
+char *get_option_arg(struct option_lst *options, e_flag flag)
+{
+	if (!options)
+		return 0;
+	for (struct option_lst *it = options; it; it = it->next)
+		if (it->flag == flag)
+			return it->arg;
+	return 0;
+}
+
+static int add_option(struct option_lst **head, e_flag flag, char *arg)
+{
+	struct option_lst *new_option = malloc(sizeof(struct option_lst));
+	if (!new_option) {
+		dprintf(2, "ft_ping: allocation of option failed\n");
+		for (struct option_lst *it = *head; it;) {
+			struct option_lst *tmp = it;
+			it = it->next;
+			free(tmp);
+		}
+		return -1;
+	}
+
+	new_option->flag = flag;
+	new_option->arg = arg;
+	new_option->next = NULL;
+
+	if (*head == NULL) {
+		*head = new_option;
+		return 0;
+	}
+	for (struct option_lst *it = *head; it; it = it->next) {
+		if (it->next == NULL) {
+			it->next = new_option;
+			break;
+		}
+	}
+	return 0;
+}
+
+struct option_lst *parse_options(int ac, char *const *av)
+{
+	struct option_lst *head = NULL;
+	const struct option options[NB_OPTIONS] = {
+	    {"help", no_argument, 0, 0},
+	    {"ports", required_argument, 0, 0},
+	    {"ip", required_argument, 0, 0},
+	    {"speedup", required_argument, 0, 0},
+	    {"scan", required_argument, 0, 0},
+	};
+
+	int c;
+	while (1) {
+		int option_index = 0;
+		c = getopt_long(ac, av, "", options, &option_index);
+		if (c == -1)
+			break;
+		else if (c)
+			return NULL;
+		if (add_option(&head, option_index, optarg) < 0)
+			return NULL;
+	}
+	return head;
+}

src/scan.c

@@ -19,21 +19,22 @@ static void dispatch_callback(u_char *user, const struct pcap_pkthdr *h,
 	const struct scan *data = (struct scan *)user;
 	const struct iphdr *iphdr =
 	    (struct iphdr *)(bytes + sizeof(struct ether_header));
-	const void *packet = bytes + sizeof(struct ether_header) + sizeof(struct iphdr);
+	const void *packet =
+	    bytes + sizeof(struct ether_header) + sizeof(struct iphdr);
 
 	if (iphdr->protocol == IPPROTO_TCP &&
 	    h->caplen >= sizeof(struct ether_header) + sizeof(struct iphdr) +
 	                     sizeof(struct tcphdr)) {
 		tcp_response(packet, data);
-	}
-	else if (iphdr->protocol == IPPROTO_UDP &&
-	    h->caplen >= sizeof(struct ether_header) + sizeof(struct iphdr) +
-	                     sizeof(struct udphdr)) {
+	} else if (iphdr->protocol == IPPROTO_UDP &&
+	           h->caplen >= sizeof(struct ether_header) +
+	                            sizeof(struct iphdr) +
+	                            sizeof(struct udphdr)) {
 		udp_response(packet, data);
-	}
-	else if (iphdr->protocol == IPPROTO_ICMP &&
-	    h->caplen >= sizeof(struct ether_header) + sizeof(struct iphdr) +
-	                     sizeof(struct icmphdr)) {
+	} else if (iphdr->protocol == IPPROTO_ICMP &&
+	           h->caplen >= sizeof(struct ether_header) +
+	                            sizeof(struct iphdr) +
+	                            sizeof(struct icmphdr)) {
 		icmp_response(packet, data);
 	}
 }
@@ -43,7 +44,7 @@ int scan(const struct scan *data)
 	int sockfd = socket(AF_INET, SOCK_RAW,
 	                    data->type == SCAN_UDP ? IPPROTO_UDP : IPPROTO_TCP);
 	if (sockfd < 0) {
-		dprintf(2, "ft_nmap: failed to create socket");
+		dprintf(2, "ft_nmap: failed to create socket\n");
 		return -1;
 	}