Hi, Following on from a previous (now lost :-)) posting, I have been trying to send out IPv6 packets from a kernel module using the kern_sendmsg() function. Since in theory I need this function to be started in interrupt context (actually, softirq context), but since this is impossible because kern_sendmsg() needs to sleep, I have created a work queue which calls the kern_sendmsg() function separately. The work queue is scheduled from the softirq context (actually, at the moment this happens from a Netfilter hook). The work queue function creates a msghdr structure, fills in a sin6_addr structure, calls sock_create_kern() and then uses this socket to send an IPv6 packet, which consists of a header (struct ipv6hdr *iphdr) and some data following on from this. The above packet is placed in the msghdr structure by setting (after the appropriate initializations): msg.msg_iov->iov_base = (char *) ip6hdr; msg.msg_iov->iov_len = sizeof( struct ipv6hdr + ntohs( ip6hdr->payload_len ) ); msg.msg_iovlen = 1; msg.msg_name = &sin6addr; msg.msg_namelen = sizeof( struct sin6_addr ); However, when trying to send this using kern_sendmsg() (or even sock_sendmsg()) to perform the send operation, I get an error (-22 - EINVAL), which, according to the user-space sendmsg(), corresponds to: "The sum of the iov_len values overflows an ssize_t. " Certainly this is not the case, since the packet in question is an ICMPv6 ping packet whose header size and data would rarely exceed 100 bytes. The test is being run on kernel 2.6.18. From what I have read on the internet, in books and in a previous suggestion from the netdev mailing-list, the use of kern_sendmsg() seems to be the appropriate way of sending packets from a kernel module. Am I doing something incorrectly above, or should I be using some other function instead of kern_sendmsg() (or sock_sendmsg())?
I would appreciate any ideas. Regards, Anton IMPORTANT: This email remains the property of the Australian Defence Organisation and is subject to the jurisdiction of section 70 of the CRIMES ACT 1914. If you have received this email in error, you are requested to contact the sender and delete the email. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
