From patch description:
This patch adds IPPROTO_ICMP socket kind. It makes it possible to send ICMP_ECHO messages and receive corresponding ICMP_ECHOREPLY messages without any special privileges. In other words, the patch makes it possible to implement setuid-less /bin/ping. A new ping socket is created with socket(PF_INET, SOCK_DGRAM, IPPROTO_ICMP) Message identifiers (octets 4-5 of ICMP header) are interpreted as local ports. Addresses are stored in struct sockaddr_in. No port numbers are reserved for privileged processes, port 0 is reserved for API ("let the kernel pick a free number"). There is no notion of remote ports, remote port numbers provided by the user (e.g. in connect()) are ignored. Data sent and received include ICMP headers. This is deliberate to: 1) Avoid the need to transport headers values like sequence numbers by other means 2) Make it easier to port existing programs using raw sockets. ICMP headers given to send() are checked and sanitized. The type must be ICMP_ECHO and the code must be zero (future extensions might relax this, see below). The id is set to the number (local port) of the socket, the checksum is always recomputed. ICMP reply packets received from the network are demultiplexed according to their id's and returned by recv() without any modifications. IP header information and ICMP errors of those packets may be obtained via ancillary data (IP_RECVTTL, IP_RETOPTS, and IP_RECVERR). ICMP source quenches and redirects are reported as fake errors via the error queue (IP_RECVERR); the next hop address for redirects is saved to ee_info (in network order). The existing code might be (in the unlikely case anyone needs it) extended rather easily to handle other similar pairs of ICMP messages (Timestamp/Reply, Information Request/Reply, Address Mask Request/Reply etc.). Initially this functionality was written by Pavel Kankovsky for Linux 2.4.32, but unfortunately it was never made public.
Userspace ping utility & patch for it:
For iputils-s20101006 (as of this writing):
(the relevant patch in the latter directory is iputils-s20101006-owl-pingsock.diff).
Patch for Linux 2.6.37-rc7 (should work with minor changes on other kernels with net namespace support): linux-2.6.37-rc7-ping2.diff
Patch for Linux 2.6.18 (RHEL+OVZ+Owl): linux-2.6.18-194.26.1.el5.028stab079.1-owl-pingsocket3.diff
Revision that went upstream: https://lkml.org/lkml/2011/5/13/382