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Message-ID: <20100818235823.GE24125@n7mm.org>
Date: Thu, 19 Aug 2010 01:58:23 +0200
From: Grégoire Baron <baronchon@...m.org>
To: netdev@...r.kernel.org
Subject: [iproute2 v2] tc: add ACT_CSUM action support (csum)
tc: add ACT_CSUM action support (csum)
Add the iproute2 support for the ACT_CSUM action. Can be used as
following, certainly in conjunction with the ACT_PEDIT action (pedit):
# In order to DNAT (stateless) IPv4 packet from 192.168.1.100 to
# 0x12345678 (18.52.86.120), and update the IPv4 header checksum and
# the UDP checksum (the last one, only if the packet is UDP).
tc filter add eth0 prio 1 protocol ip parent ffff: \
u32 match ip src 192.168.1.100/32 flowid :1 \
action pedit munge offset 16 u32 set 0x12345678 \
pipe csum ip and udp
# In order to alter destination address of IPv6 TCP packets from fc00::1
# and correct the TCP checksum (nothing happened? except maybe for
# checksums in the TCP payload ...).
tc filter add eth0 prio 1 protocol ipv6 parent ffff: \
u32 match ip6 src fc00::1/128 match ip6 protocol 0x06 0xff flowid :1 \
action pedit munge offset 24 u32 set 0x12345678 \
pipe csum tcp
Version 2 changes:
- correction in print_csum() (bad statistics print)
Signed-off-by: Gregoire Baron <baronchon@...m.org>
---
include/linux/tc_act/tc_csum.h | 32 +++++
tc/Makefile | 1 +
tc/m_csum.c | 246 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 279 insertions(+), 0 deletions(-)
create mode 100644 include/linux/tc_act/tc_csum.h
create mode 100644 tc/m_csum.c
diff --git a/include/linux/tc_act/tc_csum.h b/include/linux/tc_act/tc_csum.h
new file mode 100644
index 0000000..a047c49
--- /dev/null
+++ b/include/linux/tc_act/tc_csum.h
@@ -0,0 +1,32 @@
+#ifndef __LINUX_TC_CSUM_H
+#define __LINUX_TC_CSUM_H
+
+#include <linux/types.h>
+#include <linux/pkt_cls.h>
+
+#define TCA_ACT_CSUM 16
+
+enum {
+ TCA_CSUM_UNSPEC,
+ TCA_CSUM_PARMS,
+ TCA_CSUM_TM,
+ __TCA_CSUM_MAX
+};
+#define TCA_CSUM_MAX (__TCA_CSUM_MAX - 1)
+
+enum {
+ TCA_CSUM_UPDATE_FLAG_IPV4HDR = 1,
+ TCA_CSUM_UPDATE_FLAG_ICMP = 2,
+ TCA_CSUM_UPDATE_FLAG_IGMP = 4,
+ TCA_CSUM_UPDATE_FLAG_TCP = 8,
+ TCA_CSUM_UPDATE_FLAG_UDP = 16,
+ TCA_CSUM_UPDATE_FLAG_UDPLITE = 32
+};
+
+struct tc_csum {
+ tc_gen;
+
+ __u32 update_flags;
+};
+
+#endif /* __LINUX_TC_CSUM_H */
diff --git a/tc/Makefile b/tc/Makefile
index 3aa9f26..101cc83 100644
--- a/tc/Makefile
+++ b/tc/Makefile
@@ -34,6 +34,7 @@ TCMODULES += m_mirred.o
TCMODULES += m_nat.o
TCMODULES += m_pedit.o
TCMODULES += m_skbedit.o
+TCMODULES += m_csum.o
TCMODULES += p_ip.o
TCMODULES += p_icmp.o
TCMODULES += p_tcp.o
diff --git a/tc/m_csum.c b/tc/m_csum.c
new file mode 100644
index 0000000..d251335
--- /dev/null
+++ b/tc/m_csum.c
@@ -0,0 +1,246 @@
+/*
+ * m_csum.c checksum updating action
+ *
+ * This program is free software; you can distribute 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.
+ *
+ * Authors: Gregoire Baron <baronchon@...m.org>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <linux/tc_act/tc_csum.h>
+
+#include "utils.h"
+#include "tc_util.h"
+
+static void
+explain(void)
+{
+ fprintf(stderr, "Usage: ... csum <UPDATE>\n"
+ "Where: UPDATE := <TARGET> [<UPDATE>]\n"
+ " TARGET := { ip4h | icmp | igmp |"
+ " tcp | udp | udplite | <SWEETS> }\n"
+ " SWEETS := { and | or | \'+\' }\n");
+}
+
+static void
+usage(void)
+{
+ explain();
+ exit(-1);
+}
+
+static int
+parse_csum_args(int *argc_p, char ***argv_p, struct tc_csum *sel)
+{
+ int argc = *argc_p;
+ char **argv = *argv_p;
+
+ if (argc <= 0)
+ return -1;
+
+ while(argc > 0) {
+ if ((matches(*argv, "iph") == 0) ||
+ (matches(*argv, "ip4h") == 0) ||
+ (matches(*argv, "ipv4h") == 0))
+ sel->update_flags |= TCA_CSUM_UPDATE_FLAG_IPV4HDR;
+
+ else if (matches(*argv, "icmp") == 0)
+ sel->update_flags |= TCA_CSUM_UPDATE_FLAG_ICMP;
+
+ else if (matches(*argv, "igmp") == 0)
+ sel->update_flags |= TCA_CSUM_UPDATE_FLAG_IGMP;
+
+ else if (matches(*argv, "tcp") == 0)
+ sel->update_flags |= TCA_CSUM_UPDATE_FLAG_TCP;
+
+ else if (matches(*argv, "udp") == 0)
+ sel->update_flags |= TCA_CSUM_UPDATE_FLAG_UDP;
+
+ else if (matches(*argv, "udplite") == 0)
+ sel->update_flags |= TCA_CSUM_UPDATE_FLAG_UDPLITE;
+
+ else if ((matches(*argv, "and") == 0) ||
+ (matches(*argv, "or") == 0) ||
+ (matches(*argv, "+") == 0))
+ ; /* just ignore: ... csum iph and tcp or udp */
+ else
+ break;
+ argc--;
+ argv++;
+ }
+
+ *argc_p = argc;
+ *argv_p = argv;
+
+ return 0;
+}
+
+static int
+parse_csum(struct action_util *a, int *argc_p,
+ char ***argv_p, int tca_id, struct nlmsghdr *n)
+{
+ struct tc_csum sel;
+
+ int argc = *argc_p;
+ char **argv = *argv_p;
+ int ok = 0;
+ struct rtattr *tail;
+
+ memset(&sel, 0, sizeof(sel));
+
+ while (argc > 0) {
+ if (matches(*argv, "csum") == 0) {
+ NEXT_ARG();
+ if (parse_csum_args(&argc, &argv, &sel)) {
+ fprintf(stderr, "Illegal csum construct (%s)\n",
+ *argv);
+ explain();
+ return -1;
+ }
+ ok++;
+ continue;
+ } else if (matches(*argv, "help") == 0) {
+ usage();
+ }
+ else {
+ break;
+ }
+ }
+
+ if (!ok) {
+ explain();
+ return -1;
+ }
+
+ if (sel.update_flags == 0) {
+ fprintf(stderr, "Illegal csum construct, empty <UPDATE> list\n");
+ return -1;
+ }
+
+ if (argc) {
+ if (matches(*argv, "reclassify") == 0) {
+ sel.action = TC_ACT_RECLASSIFY;
+ argc--;
+ argv++;
+ } else if (matches(*argv, "pipe") == 0) {
+ sel.action = TC_ACT_PIPE;
+ argc--;
+ argv++;
+ } else if (matches(*argv, "drop") == 0 ||
+ matches(*argv, "shot") == 0) {
+ sel.action = TC_ACT_SHOT;
+ argc--;
+ argv++;
+ } else if (matches(*argv, "continue") == 0) {
+ sel.action = TC_ACT_UNSPEC;
+ argc--;
+ argv++;
+ } else if (matches(*argv, "pass") == 0) {
+ sel.action = TC_ACT_OK;
+ argc--;
+ argv++;
+ }
+ }
+
+ if (argc) {
+ if (matches(*argv, "index") == 0) {
+ NEXT_ARG();
+ if (get_u32(&sel.index, *argv, 10)) {
+ fprintf(stderr, "Illegal \"index\" (%s) <csum>\n",
+ *argv);
+ return -1;
+ }
+ argc--;
+ argv++;
+ }
+ }
+
+ tail = NLMSG_TAIL(n);
+ addattr_l(n, MAX_MSG, tca_id, NULL, 0);
+ addattr_l(n, MAX_MSG, TCA_CSUM_PARMS, &sel, sizeof(sel));
+ tail->rta_len = (char *)NLMSG_TAIL(n) - (char *)tail;
+
+ *argc_p = argc;
+ *argv_p = argv;
+
+ return 0;
+}
+
+static int
+print_csum(struct action_util *au, FILE * f, struct rtattr *arg)
+{
+ struct tc_csum *sel;
+
+ struct rtattr *tb[TCA_CSUM_MAX + 1];
+
+ char *uflag_1 = "";
+ char *uflag_2 = "";
+ char *uflag_3 = "";
+ char *uflag_4 = "";
+ char *uflag_5 = "";
+ char *uflag_6 = "";
+ SPRINT_BUF(action_buf);
+
+ int uflag_count = 0;
+
+ if (arg == NULL)
+ return -1;
+
+ parse_rtattr_nested(tb, TCA_CSUM_MAX, arg);
+
+ if (tb[TCA_CSUM_PARMS] == NULL) {
+ fprintf(f, "[NULL csum parameters]");
+ return -1;
+ }
+ sel = RTA_DATA(tb[TCA_CSUM_PARMS]);
+
+ if (sel->update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
+ uflag_1 = "iph";
+ uflag_count++;
+ }
+ #define CSUM_UFLAG_BUFFER(flag_buffer, flag_value, flag_string) \
+ do { \
+ if (sel->update_flags & flag_value) { \
+ flag_buffer = uflag_count > 0 ? \
+ ", " flag_string : flag_string; \
+ uflag_count++; \
+ } \
+ } while(0)
+ CSUM_UFLAG_BUFFER(uflag_2, TCA_CSUM_UPDATE_FLAG_ICMP, "icmp");
+ CSUM_UFLAG_BUFFER(uflag_3, TCA_CSUM_UPDATE_FLAG_IGMP, "igmp");
+ CSUM_UFLAG_BUFFER(uflag_4, TCA_CSUM_UPDATE_FLAG_TCP, "tdp");
+ CSUM_UFLAG_BUFFER(uflag_5, TCA_CSUM_UPDATE_FLAG_UDP, "udp");
+ CSUM_UFLAG_BUFFER(uflag_6, TCA_CSUM_UPDATE_FLAG_UDPLITE, "udplite");
+ if (!uflag_count) {
+ uflag_1 = "?empty";
+ }
+
+ fprintf(f, "csum (%s%s%s%s%s%s) action %s\n",
+ uflag_1, uflag_2, uflag_3,
+ uflag_4, uflag_5, uflag_6,
+ action_n2a(sel->action, action_buf, sizeof(action_buf)));
+ fprintf(f, "\tindex %d ref %d bind %d", sel->index, sel->refcnt, sel->bindcnt);
+
+ if (show_stats) {
+ if (tb[TCA_CSUM_TM]) {
+ struct tcf_t *tm = RTA_DATA(tb[TCA_CSUM_TM]);
+ print_tm(f,tm);
+ }
+ }
+ fprintf(f, "\n");
+
+ return 0;
+}
+
+struct action_util csum_action_util = {
+ .id = "csum",
+ .parse_aopt = parse_csum,
+ .print_aopt = print_csum,
+};
--
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