pespin has uploaded this change for review. ( https://gerrit.osmocom.org/c/libosmo-netif/+/42463?usp=email )

Change subject: Introduce ip_checksum API ......................................................................

Introduce ip_checksum API

ip_checksum.* files are copied from checksum.* in osmo-ggsn.git 1.14.0 (ebd1bf8adbc8d5bec9e36d70e3a78e8838226e7a).

Change-Id: Ia09645a4715ac133036d7c89297b0fa10cf9aa3b --- M TODO-RELEASE M include/osmocom/netif/Makefile.am A include/osmocom/netif/ip_checksum.h M src/Makefile.am A src/ip_checksum.c 5 files changed, 226 insertions(+), 0 deletions(-)

git pull ssh://gerrit.osmocom.org:29418/libosmo-netif refs/changes/63/42463/1

diff --git a/TODO-RELEASE b/TODO-RELEASE index 0ed7189..7aebf84 100644 --- a/TODO-RELEASE +++ b/TODO-RELEASE @@ -7,3 +7,4 @@ # If any interfaces have been added since the last public release: c:r:a + 1. # If any interfaces have been removed or changed since the last public release: c:r:0. #library what description / commit summary line +netif add osmo_ip_checksum API diff --git a/include/osmocom/netif/Makefile.am b/include/osmocom/netif/Makefile.am index 71f0931..f509221 100644 --- a/include/osmocom/netif/Makefile.am +++ b/include/osmocom/netif/Makefile.am @@ -20,6 +20,7 @@ osmonetif_HEADERS = \ amr.h \ datagram.h \ + ip_checksum.h \ ipa.h \ ipa_unit.h \ jibuf.h \ diff --git a/include/osmocom/netif/ip_checksum.h b/include/osmocom/netif/ip_checksum.h new file mode 100644 index 0000000..b5130ee --- /dev/null +++ b/include/osmocom/netif/ip_checksum.h @@ -0,0 +1,11 @@ +#pragma once +#include <stdint.h> +#include <netinet/in.h> + +uint16_t osmo_ip_checksum_fast_csum(const void *iph, unsigned int ihl); +uint32_t osmo_ip_checksum_csum_partial(const void *buff, int len, uint32_t wsum); +uint16_t osmo_ip_checksum_compute_csum(const void *buff, int len); + +uint16_t osmo_ip_checksum_csum_ipv6_magic(const struct in6_addr *saddr, + const struct in6_addr *daddr, + uint32_t len, uint8_t proto, uint32_t csum); diff --git a/src/Makefile.am b/src/Makefile.am index 753bac2..4484e02 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -15,6 +15,7 @@

libosmonetif_la_SOURCES = amr.c \ datagram.c \ + ip_checksum.c \ ipa.c \ ipa_keepalive.c \ ipa_unit.c \ diff --git a/src/ip_checksum.c b/src/ip_checksum.c new file mode 100644 index 0000000..1fa6f42 --- /dev/null +++ b/src/ip_checksum.c @@ -0,0 +1,212 @@ +/* + * + * INET An implementation of the TCP/IP protocol suite for the LINUX + * operating system. INET is implemented using the BSD Socket + * interface as the means of communication with the user level. + * + * IP/TCP/UDP checksumming routines + * + * Authors: Jorge Cwik, jorge@laser.satlink.net + * Arnt Gulbrandsen, agulbra@nvg.unit.no + * Tom May, ftom@netcom.com + * Andreas Schwab, schwab@issan.informatik.uni-dortmund.de + * Lots of code moved from tcp.c and ip.c; see those files + * for more names. + * + * 03/02/96 Jes Sorensen, Andreas Schwab, Roman Hodek: + * Fixed some nasty bugs, causing some horrible crashes. + * A: At some points, the sum (%0) was used as + * length-counter instead of the length counter + * (%1). Thanks to Roman Hodek for pointing this out. + * B: GCC seems to mess up if one uses too many + * data-registers to hold input values and one tries to + * specify d0 and d1 as scratch registers. Letting gcc + * choose these registers itself solves the problem. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +/* Revised by Kenneth Albanowski for m68knommu. Basic problem: unaligned access + kills, so most of the assembly has to go. */ + +#if defined(__FreeBSD__) +#define _KERNEL /* needed on FreeBSD 10.x for s6_addr32 */ +#include <sys/types.h> +#include <netinet/in.h> +#include <sys/endian.h> +#endif + +#include <arpa/inet.h> + +#include <osmocom/netif/ip_checksum.h> + +static inline unsigned short from32to16(unsigned int x) +{ + /* add up 16-bit and 16-bit for 16+c bit */ + x = (x & 0xffff) + (x >> 16); + /* add up carry.. */ + x = (x & 0xffff) + (x >> 16); + return x; +} + +static unsigned int do_csum(const unsigned char *buff, int len) +{ + int odd; + unsigned int result = 0; + + if (len <= 0) + goto out; + odd = 1 & (unsigned long) buff; + if (odd) { +#if BYTE_ORDER == LITTLE_ENDIAN + result += (*buff << 8); +#else + result = *buff; +#endif + len--; + buff++; + } + if (len >= 2) { + if (2 & (unsigned long) buff) { + result += *(unsigned short *) buff; + len -= 2; + buff += 2; + } + if (len >= 4) { + const unsigned char *end = buff + ((unsigned)len & ~3); + unsigned int carry = 0; + do { + unsigned int w = *(unsigned int *) buff; + buff += 4; + result += carry; + result += w; + carry = (w > result); + } while (buff < end); + result += carry; + result = (result & 0xffff) + (result >> 16); + } + if (len & 2) { + result += *(unsigned short *) buff; + buff += 2; + } + } + if (len & 1) +#if BYTE_ORDER == LITTLE_ENDIAN + result += *buff; +#else + result += (*buff << 8); +#endif + result = from32to16(result); + if (odd) + result = ((result >> 8) & 0xff) | ((result & 0xff) << 8); +out: + return result; +} + +/* fold a partial checksum */ +static uint16_t csum_fold(uint32_t csum) +{ + uint32_t sum = (uint32_t)csum; + sum = (sum & 0xffff) + (sum >> 16); + sum = (sum & 0xffff) + (sum >> 16); + return (uint16_t)~sum; +} + +/* + * This is a version of ip_compute_csum() optimized for IP headers, + * which always checksum on 4 octet boundaries. + */ +uint16_t osmo_ip_checksum_fast_csum(const void *iph, unsigned int ihl) +{ + return (uint16_t)~do_csum(iph, ihl*4); +} + +/* + * computes the checksum of a memory block at buff, length len, + * and adds in "sum" (32-bit) + * + * returns a 32-bit number suitable for feeding into itself + * or csum_tcpudp_magic + * + * this function must be called with even lengths, except + * for the last fragment, which may be odd + * + * it's best to have buff aligned on a 32-bit boundary + */ +uint32_t osmo_ip_checksum_csum_partial(const void *buff, int len, uint32_t wsum) +{ + unsigned int sum = (unsigned int)wsum; + unsigned int result = do_csum(buff, len); + + /* add in old sum, and carry.. */ + result += sum; + if (sum > result) + result += 1; + return (uint32_t)result; +} + +/* + * this routine is used for miscellaneous IP-like checksums, mainly + * in icmp.c + */ +uint16_t osmo_ip_checksum_compute_csum(const void *buff, int len) +{ + return (uint16_t)~do_csum(buff, len); +} + +uint16_t osmo_ip_checksum_csum_ipv6_magic(const struct in6_addr *saddr, + const struct in6_addr *daddr, + uint32_t len, uint8_t proto, uint32_t csum) +{ + int carry; + uint32_t ulen; + uint32_t uproto; + uint32_t sum = (uint32_t)csum; + + sum += (uint32_t)saddr->s6_addr32[0]; + carry = (sum < (uint32_t)saddr->s6_addr32[0]); + sum += carry; + + sum += (uint32_t)saddr->s6_addr32[1]; + carry = (sum < (uint32_t)saddr->s6_addr32[1]); + sum += carry; + + sum += (uint32_t)saddr->s6_addr32[2]; + carry = (sum < (uint32_t)saddr->s6_addr32[2]); + sum += carry; + + sum += (uint32_t)saddr->s6_addr32[3]; + carry = (sum < (uint32_t)saddr->s6_addr32[3]); + sum += carry; + + sum += (uint32_t)daddr->s6_addr32[0]; + carry = (sum < (uint32_t)daddr->s6_addr32[0]); + sum += carry; + + sum += (uint32_t)daddr->s6_addr32[1]; + carry = (sum < (uint32_t)daddr->s6_addr32[1]); + sum += carry; + + sum += (uint32_t)daddr->s6_addr32[2]; + carry = (sum < (uint32_t)daddr->s6_addr32[2]); + sum += carry; + + sum += (uint32_t)daddr->s6_addr32[3]; + carry = (sum < (uint32_t)daddr->s6_addr32[3]); + sum += carry; + + ulen = (uint32_t)htonl((uint32_t) len); + sum += ulen; + carry = (sum < ulen); + sum += carry; + + uproto = (uint32_t)htonl(proto); + sum += uproto; + carry = (sum < uproto); + sum += carry; + + return csum_fold((uint32_t)sum); +}