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author | Franciszek Malinka <franciszek.malinka@gmail.com> | 2021-03-16 19:31:22 +0100 |
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committer | Franciszek Malinka <franciszek.malinka@gmail.com> | 2021-03-16 19:31:22 +0100 |
commit | 5c974d1f80d6bbbcbbe7138fec974a79379702b2 (patch) | |
tree | bb9f6d5e4086b3b81d2a4871ca37de9208bf0b64 /Semestr 4/sieci/pracownia1/icmp_receive.c | |
parent | b7b9ebd921a5161012dfd29ffa6ca04729283e19 (diff) |
pracownia 1 z sieci
Diffstat (limited to 'Semestr 4/sieci/pracownia1/icmp_receive.c')
-rw-r--r-- | Semestr 4/sieci/pracownia1/icmp_receive.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/Semestr 4/sieci/pracownia1/icmp_receive.c b/Semestr 4/sieci/pracownia1/icmp_receive.c new file mode 100644 index 0000000..07d3b69 --- /dev/null +++ b/Semestr 4/sieci/pracownia1/icmp_receive.c @@ -0,0 +1,53 @@ +#include <netinet/ip.h> +#include <arpa/inet.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> + + +void print_as_bytes (unsigned char* buff, ssize_t length) +{ + for (ssize_t i = 0; i < length; i++, buff++) + printf ("%.2x ", *buff); +} + + +int main() +{ + int sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP); + if (sockfd < 0) { + fprintf(stderr, "socket error: %s\n", strerror(errno)); + return EXIT_FAILURE; + } + + for (;;) { + + struct sockaddr_in sender; + socklen_t sender_len = sizeof(sender); + u_int8_t buffer[IP_MAXPACKET]; + + ssize_t packet_len = recvfrom (sockfd, buffer, IP_MAXPACKET, 0, (struct sockaddr*)&sender, &sender_len); + if (packet_len < 0) { + fprintf(stderr, "recvfrom error: %s\n", strerror(errno)); + return EXIT_FAILURE; + } + + char sender_ip_str[20]; + inet_ntop(AF_INET, &(sender.sin_addr), sender_ip_str, sizeof(sender_ip_str)); + printf ("Received IP packet with ICMP content from: %s\n", sender_ip_str); + + struct ip* ip_header = (struct ip*) buffer; + ssize_t ip_header_len = 4 * ip_header->ip_hl; + + printf ("IP header: "); + print_as_bytes (buffer, ip_header_len); + printf("\n"); + + printf ("IP data: "); + print_as_bytes (buffer + ip_header_len, packet_len - ip_header_len); + printf("\n\n"); + } + + return EXIT_SUCCESS; +} |