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Mar 2024 10:55:52 -0700 (PDT) Date: Sun, 17 Mar 2024 09:55:50 -0400 From: Oliver Crumrine To: alx@kernel.org Cc: linux-kernel@vger.kernel.org, linux-man@vger.kernel.org Subject: [PATCH] ip.7: Add not supported by SOCK_STREAM to socket options Message-ID: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="cnsbju7h52latmr3" Content-Disposition: inline Content-Transfer-Encoding: quoted-printable --cnsbju7h52latmr3 Content-Disposition: inline MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 SXQgd2FzIG5vdCBtYWRlIGNsZWFyIGluIHNldmVyYWwgc29ja2V0IG9wdGlvbnMgdGhhdCB0aGV5 IHdlcmUgbm90CnN1cHBvcnRlZCBieSBTT0NLX1NUUkVBTTsgdGhpcyBwYXRjaCBmaXhlcyB0aGF0 LgoKU29ja2V0IG9wdGlvbnMgbm90IHN1cHBvcnRlZCBieSBTT0NLX1NUUkVBTSBhcmUgaGFuZGxl ZCBpbiB0aGUKaXBfY21zZ19yZWN2X29mZnNldCBmdW5jdGlvbiBpbiBuZXQvaXB2NC9pcF9zb2Nr 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IPPROTO_UDP); if(s == -1){ err(1, "error creating socket"); } uint8_t options = 1; //noop in the language of ip options if(setsockopt(s, IPPROTO_IP, IP_OPTIONS, &options, 1) == -1){ err(1, "error setting socket options"); } memset(&server_addr, 0, sizeof(server_addr)); server_addr.sin_family = AF_INET; server_addr.sin_port = htons(PORT); if(inet_pton(AF_INET, ADDR, &server_addr.sin_addr) != 1){ // I realize I'm checking the return value differently here. If you read the man page for inet_pton, it'll make sense. err(1, "error converting network address"); } if(sendto(s, buf, strlen(buf), 0, (struct sockaddr*)&server_addr, sizeof(server_addr)) == -1){ err(1, "error sending data"); } close(s); } --cnsbju7h52latmr3 Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="testDgramSocketServer.c" #include #include #include #include #include #include #include #define PORT 8888 //The port on which to listen for incoming data //Hi Alex, //These are the two lines that allow you to switch between the three socket options outlined in my patch //The socket options tell the kernel to add a control message (cmsg), allowing the program //to recieve the data it is requesting. The three options are: IP_RECVTOS for the type of service byte, //IP_RECVORIGDSTADDR for the orignial dst address, and IP_PKTINFO for some random packet info, and IP_RETOPTS //for some random ip packet options #define SOCKOPT IP_RECVORIGDSTADDR //This field is synonymous with the above one. Valid options are: IP_TOS, IP_ORIGDSTADDR, IP_PKTINFO, and IP_OPTIONS #define RECIVEOPTION IP_ORIGDSTADDR int main(void){ struct sockaddr_in local_addr; int s; s = socket(AF_INET, SOCK_DGRAM, 0); if (s == -1){ err(1, "error creating socket"); } memset(&local_addr, 0, sizeof(local_addr)); local_addr.sin_family = AF_INET; local_addr.sin_port = htons(PORT); local_addr.sin_addr.s_addr = htonl(INADDR_ANY); int yes = 1; if(setsockopt(s, IPPROTO_IP, SOCKOPT, &yes, sizeof(yes)) == -1){ err(1, "error setting socket option"); } if(bind(s, (struct sockaddr*)&local_addr, sizeof(local_addr) ) == -1){ err(1, "error binding to port. try changing it or running as root"); } while(1){ struct msghdr mhdr; struct iovec iov[1]; struct cmsghdr *cmhdr; char control[1000]; char databuf[BUFSIZ]; unsigned char tos = 0; mhdr.msg_name = &local_addr; mhdr.msg_namelen = sizeof(local_addr); mhdr.msg_iov = iov; mhdr.msg_iovlen = 1; mhdr.msg_control = &control; mhdr.msg_controllen = sizeof(control); iov[0].iov_base = databuf; iov[0].iov_len = sizeof(databuf); memset(databuf, 0, sizeof(databuf)); //this is blocking int msglen = recvmsg(s, &mhdr, 0); if (msglen == -1){ err(1, "recvmsg"); } cmhdr = CMSG_FIRSTHDR(&mhdr); while (cmhdr) { printf("cmsg recieved\n"); if (cmhdr->cmsg_level == IPPROTO_IP && cmhdr->cmsg_type == RECIVEOPTION) { //read the byte recieved tos = ((unsigned char *)CMSG_DATA(cmhdr))[0]; } cmhdr = CMSG_NXTHDR(&mhdr, cmhdr); } //print out the first byte of data recieved in hex. You can verify this in wireshark if you like. printf("data read: %sbyte = %02X\n", databuf, tos); } close(s); return 0; } --cnsbju7h52latmr3 Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="testStreamSocketClient.c" #include #include #include #include #include #include #include #define PORT 8888 //The port on which to send data #define ADDR "127.0.0.1" //The internet address to send packets to int main(void){ int s; struct sockaddr_in server_addr; char buf[] = "testing 1 2 3\n"; s = socket(AF_INET, SOCK_STREAM, 0); if(s == -1){ err(1, "error creating socket"); } uint8_t options = 1; //noop in the language of ip options if(setsockopt(s, IPPROTO_IP, IP_OPTIONS, &options, 1) == -1){ err(1, "error setting socket options"); } memset(&server_addr, 0, sizeof(server_addr)); server_addr.sin_family = AF_INET; server_addr.sin_port = htons(PORT); if(inet_pton(AF_INET, ADDR, &server_addr.sin_addr) != 1){ // I realize I'm checking the return value differently here. If you read the man page for inet_pton, it'll make sense. err(1, "error converting network address"); } if(connect(s, (struct sockaddr*)&server_addr, sizeof(server_addr)) == -1){ err(1, "error connecting"); } if(send(s, buf, strlen(buf), 0) == -1){ err(1, "error sending data"); } close(s); } --cnsbju7h52latmr3 Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="testStreamSocketServer.c" #include #include #include #include #include #include #include #define PORT 8888 //The port on which to listen for incoming data //Hi Alex, //These are the two lines that allow you to switch between the three socket options outlined in my patch //The socket options tell the kernel to add a control message (cmsg), allowing the program //to recieve the data it is requesting. The three options are: IP_RECVTOS for the type of service byte, //IP_RECVORIGDSTADDR for the orignial dst address, and IP_PKTINFO for some random packet info, and IP_RETOPTS //for some random ip packet options #define SOCKOPT IP_RECVORIGDSTADDR //This field is synonymous with the above one. Valid options are: IP_TOS, IP_ORIGDSTADDR, IP_PKTINFO, and IP_OPTIONS #define RECIVEOPTION IP_ORIGDSTADDR int main(void){ struct sockaddr_in local_addr; int s; s = socket(AF_INET, SOCK_STREAM, 0); if (s == -1){ err(1, "error creating socket"); } memset(&local_addr, 0, sizeof(local_addr)); local_addr.sin_family = AF_INET; local_addr.sin_port = htons(PORT); local_addr.sin_addr.s_addr = htonl(INADDR_ANY); int yes = 1; if(setsockopt(s, IPPROTO_IP, SOCKOPT, &yes, sizeof(yes)) == -1){ err(1, "error setting socket option"); } if(bind(s, (struct sockaddr*)&local_addr, sizeof(local_addr) ) == -1){ err(1, "error binding to port. try changing it or running as root"); } if(listen(s, 10) == -1){ //10 is the backlog of un-accepted connections. its just an arbitrary number err(1, "error listening on port"); } while(1){ int connfd = accept(s, (struct sockaddr*)NULL, NULL); if(connfd == -1){ err(1, "error accepting connection"); } if(setsockopt(s, IPPROTO_IP, SOCKOPT, &yes, sizeof(yes)) == -1){ //stream sockets should have this set on the connected socket as well. I left it above for uniformity between the two programs. err(1, "error setting socket option"); } struct msghdr mhdr; struct iovec iov[1]; struct cmsghdr *cmhdr; char control[1000]; char databuf[BUFSIZ]; unsigned char tos = 0; mhdr.msg_name = &local_addr; mhdr.msg_namelen = sizeof(local_addr); mhdr.msg_iov = iov; mhdr.msg_iovlen = 1; mhdr.msg_control = &control; mhdr.msg_controllen = sizeof(control); iov[0].iov_base = databuf; iov[0].iov_len = sizeof(databuf); memset(databuf, 0, sizeof(databuf)); //this is blocking int msglen = recvmsg(connfd, &mhdr, 0); if (msglen == -1){ err(1, "recvmsg"); } cmhdr = CMSG_FIRSTHDR(&mhdr); while (cmhdr) { printf("cmsg recieved\n"); if (cmhdr->cmsg_level == IPPROTO_IP && cmhdr->cmsg_type == RECIVEOPTION) { //read the byte recieved tos = ((unsigned char *)CMSG_DATA(cmhdr))[0]; } cmhdr = CMSG_NXTHDR(&mhdr, cmhdr); } //print out the first byte of data recieved in hex. You can verify this in wireshark if you like. printf("data read: %sbyte = %02X\n", databuf, tos); close(connfd); } close(s); return 0; } --cnsbju7h52latmr3--