It was not made clear in several socket options that they were not
supported by SOCK_STREAM; this patch fixes that.
Socket options not supported by SOCK_STREAM are handled in the
ip_cmsg_recv_offset function in net/ipv4/ip_sockglue.c. The function is
called for udp sockets, and indirectly by ping and raw sockets, but not
for STREAM sockets, as they don't support these options.
Signed-off-by: Oliver Crumrine <ozlinuxc@xxxxxxxxx>
v1->v2: Add IP_RETOPTS to the socket options without support on
SOCK_STREAM
Alex, I have attached the two test programs below, updated for support
with IP_RETOPTS.
I couldn't get an ip option out of netcat, so I'm attaching the client
programs, also updated with support for IP_OPTIONS, so they put an ip
option onto the packet for the server program to recieve.
Here is the diff between the two servers:
--- testDgramSocketServer.c 2024-03-17 08:32:27.623451419 -0400
+++ testStreamSocketServer.c 2024-03-17 08:21:11.860109033 -0400
@@ -23,7 +23,7 @@
struct sockaddr_in local_addr;
int s;
- s = socket(AF_INET, SOCK_DGRAM, 0);
+ s = socket(AF_INET, SOCK_STREAM, 0);
if (s == -1){
err(1, "error creating socket");
}
@@ -43,8 +43,20 @@
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;
@@ -63,7 +75,7 @@
memset(databuf, 0, sizeof(databuf));
//this is blocking
- int msglen = recvmsg(s, &mhdr, 0);
+ int msglen = recvmsg(connfd, &mhdr, 0);
if (msglen == -1){
err(1, "recvmsg");
}
@@ -78,6 +90,7 @@
}
//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);
And the clients in case you're interested:
--- testDgramSocketClient.c 2024-03-17 08:24:07.640111430 -0400
+++ testStreamSocketClient.c 2024-03-17 08:23:02.883443865 -0400
@@ -15,7 +15,7 @@
char buf[] = "testing 1 2 3\n";
- s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+ s = socket(AF_INET, SOCK_STREAM, 0);
if(s == -1){
err(1, "error creating socket");
}
@@ -34,7 +34,10 @@
err(1, "error converting network address");
}
- if(sendto(s, buf, strlen(buf), 0, (struct sockaddr*)&server_addr, sizeof(server_addr)) == -1){
+ 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");
}
---
man7/ip.7 | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/man7/ip.7 b/man7/ip.7
index 2b4b06324..39055d3cf 100644
--- a/man7/ip.7
+++ b/man7/ip.7
@@ -828,6 +828,9 @@ is not zero, the primary local address of the interface specified by the
index overwrites
.I ipi_spec_dst
for the routing table lookup.
+Not supported for
+.B SOCK_STREAM
+sockets.
.TP
.BR IP_RECVERR " (since Linux 2.2)"
.\" Precisely: since Linux 2.1.15
@@ -989,6 +992,9 @@ in which the kernel returns the original destination address
of the datagram being received.
The ancillary message contains a
.IR "struct sockaddr_in" .
+Not supported for
+.B SOCK_STREAM
+sockets.
.TP
.BR IP_RECVTOS " (since Linux 2.2)"
.\" Precisely: since Linux 2.1.68
@@ -998,6 +1004,9 @@ ancillary message is passed with incoming packets.
It contains a byte which specifies the Type of Service/Precedence
field of the packet header.
Expects a boolean integer flag.
+Not supported for
+.B SOCK_STREAM
+sockets.
.TP
.BR IP_RECVTTL " (since Linux 2.2)"
.\" Precisely: since Linux 2.1.68
@@ -1015,6 +1024,9 @@ Identical to
.BR IP_RECVOPTS ,
but returns raw unprocessed options with timestamp and route record
options not filled in for this hop.
+Not supported for
+.B SOCK_STREAM
+sockets.
.TP
.BR IP_ROUTER_ALERT " (since Linux 2.2)"
.\" Precisely: since Linux 2.1.68
--
2.44.0
#include <stdio.h>
#include <err.h>
#include <string.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <unistd.h>
#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_DGRAM, 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);
}
#include<stdio.h>
#include<err.h>
#include<string.h>
#include<stdlib.h>
#include<arpa/inet.h>
#include<sys/socket.h>
#include<unistd.h>
#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;
}
#include <stdio.h>
#include <err.h>
#include <string.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <unistd.h>
#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);
}
#include<stdio.h>
#include<err.h>
#include<string.h>
#include<stdlib.h>
#include<arpa/inet.h>
#include<sys/socket.h>
#include<unistd.h>
#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;
}
