raw-sockets

问题 I was looking into raw sockets. so I created one raw socket client and other one is server. on two different computers. I am using ISP provided router. so I sent spoofed packet (with iphdr struct's saddr of different computer on same network) from client but when the packet received at the server the source ip in packet's ip header was correct (the real sender address=client address) plus the source port and destination port of tcphdr were something different too (which really didnt make

问题 I was looking into raw sockets. so I created one raw socket client and other one is server. on two different computers. I am using ISP provided router. so I sent spoofed packet (with iphdr struct's saddr of different computer on same network) from client but when the packet received at the server the source ip in packet's ip header was correct (the real sender address=client address) plus the source port and destination port of tcphdr were something different too (which really didnt make

问题 I'm trying to implement my own transport layer protocol, but I'm perfectly happy to leave the network layer as-is and not need to mess with the actual IP header information. But of course, when calling recvfrom() on a raw socket, you are given the raw IP datagram, while the sockaddr struct is not filled in. Is there anyway to coax the stack to fill in those structs and leave the ip header out of the data portion, or does that need to be implemented by hand? Receiver: struct sockaddr_in sender

问题 I'm trying to implement my own transport layer protocol, but I'm perfectly happy to leave the network layer as-is and not need to mess with the actual IP header information. But of course, when calling recvfrom() on a raw socket, you are given the raw IP datagram, while the sockaddr struct is not filled in. Is there anyway to coax the stack to fill in those structs and leave the ip header out of the data portion, or does that need to be implemented by hand? Receiver: struct sockaddr_in sender

问题 My code sends a raw IP packet to 12.12.12.12 and fails because of EMSGSIZE . I think that it limits my packet according to Ethernet MTU, but it should send packets <= 65,535 bytes (IPv4 MTU). I've tried to send a packet to 127.0.0.1 and this worked well, but the error occurs when I send a packet to a non-local IP. #include <assert.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <sys/types.h> #include <netinet/in.h> #include <arpa/inet.h> int main(void) { int fd;

问题 My code sends a raw IP packet to 12.12.12.12 and fails because of EMSGSIZE . I think that it limits my packet according to Ethernet MTU, but it should send packets <= 65,535 bytes (IPv4 MTU). I've tried to send a packet to 127.0.0.1 and this worked well, but the error occurs when I send a packet to a non-local IP. #include <assert.h> #include <string.h> #include <unistd.h> #include <sys/socket.h> #include <sys/types.h> #include <netinet/in.h> #include <arpa/inet.h> int main(void) { int fd;

问题 I need to receive incoming UDP packets using RAW socket, which is being opened using this code snippet: static int fd; char *iface; iface = "eth0"; if ( (fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP))) < 0 ) { perror("socket"); } if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, iface, strlen(iface)) < 0) { perror("bind"); exit(EXIT_FAILURE); } I send, say, 100 identical packets and try to receive and count them. I use recv(...) to do this. Only 93 packets are delivered, and then recv(...)

问题 I like to know the source port of packet in tcphdr can be assigned to destination port of ip like this source_ip_tcph->source= dest_ip_tcph->dest; source_ip_tcph->dest = dest_ip_tcph->source; above are source and destination (pointer to memory) of tcphdr type I am trying to create a server everytime I respond to client from server the destination port is different. I assigned it like above Edit Above I am using raw sockets. trying to make raw socket based tcp implementation as a server 来源：

问题 I like to know the source port of packet in tcphdr can be assigned to destination port of ip like this source_ip_tcph->source= dest_ip_tcph->dest; source_ip_tcph->dest = dest_ip_tcph->source; above are source and destination (pointer to memory) of tcphdr type I am trying to create a server everytime I respond to client from server the destination port is different. I assigned it like above Edit Above I am using raw sockets. trying to make raw socket based tcp implementation as a server 来源：

问题 I like to know the source port of packet in tcphdr can be assigned to destination port of ip like this source_ip_tcph->source= dest_ip_tcph->dest; source_ip_tcph->dest = dest_ip_tcph->source; above are source and destination (pointer to memory) of tcphdr type I am trying to create a server everytime I respond to client from server the destination port is different. I assigned it like above Edit Above I am using raw sockets. trying to make raw socket based tcp implementation as a server 来源：