[PKT_SCHED]: Packet classification based on textsearch (ematch)

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 169 insertions, 0 deletions

diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index b22c9beb604d..95d9bc5d8621 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -449,6 +449,17 @@ config NET_EMATCH_META
           To compile this code as a module, choose M here: the
           module will be called em_meta.
 
+config NET_EMATCH_TEXT
+        tristate "Textsearch"
+        depends on NET_EMATCH
+        ---help---
+          Say Y here if you want to be ablt to classify packets based on
+          textsearch comparisons. Please select the appropriate textsearch
+          algorithms in the Library section.
+
+          To compile this code as a module, choose M here: the
+          module will be called em_text.
+
 config NET_CLS_ACT
         bool "Packet ACTION"
         depends on EXPERIMENTAL && NET_CLS && NET_QOS
diff --git a/net/sched/Makefile b/net/sched/Makefile
index eb3fe583eba8..8f58cecd6266 100644
--- a/net/sched/Makefile
+++ b/net/sched/Makefile
@@ -40,3 +40,4 @@ obj-$(CONFIG_NET_EMATCH_CMP)	+= em_cmp.o
 obj-$(CONFIG_NET_EMATCH_NBYTE)  += em_nbyte.o
 obj-$(CONFIG_NET_EMATCH_U32)    += em_u32.o
 obj-$(CONFIG_NET_EMATCH_META)   += em_meta.o
+obj-$(CONFIG_NET_EMATCH_TEXT)   += em_text.o
diff --git a/net/sched/em_text.c b/net/sched/em_text.c
new file mode 100644
index 000000000000..873840d8d072
--- /dev/null
+++ b/net/sched/em_text.c
@@ -0,0 +1,157 @@
+/*
+ * net/sched/em_text.c  Textsearch ematch
+ *
+ *              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.
+ *
+ * Authors:     Thomas Graf <tgraf@suug.ch>
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <linux/textsearch.h>
+#include <linux/tc_ematch/tc_em_text.h>
+#include <net/pkt_cls.h>
+
+struct text_match
+{
+        u16                     from_offset;
+        u16                     to_offset;
+        u8                      from_layer;
+        u8                      to_layer;
+        struct ts_config        *config;
+};
+
+#define EM_TEXT_PRIV(m) ((struct text_match *) (m)->data)
+
+static int em_text_match(struct sk_buff *skb, struct tcf_ematch *m,
+                         struct tcf_pkt_info *info)
+{
+        struct text_match *tm = EM_TEXT_PRIV(m);
+        int from, to;
+        struct ts_state state;
+
+        from = tcf_get_base_ptr(skb, tm->from_layer) - skb->data;
+        from += tm->from_offset;
+
+        to = tcf_get_base_ptr(skb, tm->to_layer) - skb->data;
+        to += tm->to_offset;
+
+        return skb_find_text(skb, from, to, tm->config, &state) != UINT_MAX;
+}
+
+static int em_text_change(struct tcf_proto *tp, void *data, int len,
+                          struct tcf_ematch *m)
+{
+        struct text_match *tm;
+        struct tcf_em_text *conf = data;
+        struct ts_config *ts_conf;
+        int flags = 0;
+
+        printk("Configuring text: %s from %d:%d to %d:%d len %d\n", conf->algo, conf->from_offset,
+            conf->from_layer, conf->to_offset, conf->to_layer, conf->pattern_len);
+
+        if (len < sizeof(*conf) || len < (sizeof(*conf) + conf->pattern_len))
+                return -EINVAL;
+
+        if (conf->from_layer > conf->to_layer)
+                return -EINVAL;
+
+        if (conf->from_layer == conf->to_layer &&
+            conf->from_offset > conf->to_offset)
+                return -EINVAL;
+
+retry:
+        ts_conf = textsearch_prepare(conf->algo, (u8 *) conf + sizeof(*conf),
+                                     conf->pattern_len, GFP_KERNEL, flags);
+
+        if (flags & TS_AUTOLOAD)
+                rtnl_lock();
+
+        if (IS_ERR(ts_conf)) {
+                if (PTR_ERR(ts_conf) == -ENOENT && !(flags & TS_AUTOLOAD)) {
+                        rtnl_unlock();
+                        flags |= TS_AUTOLOAD;
+                        goto retry;
+                } else
+                        return PTR_ERR(ts_conf);
+        } else if (flags & TS_AUTOLOAD) {
+                textsearch_destroy(ts_conf);
+                return -EAGAIN;
+        }
+
+        tm = kmalloc(sizeof(*tm), GFP_KERNEL);
+        if (tm == NULL) {
+                textsearch_destroy(ts_conf);
+                return -ENOBUFS;
+        }
+
+        tm->from_offset = conf->from_offset;
+        tm->to_offset   = conf->to_offset;
+        tm->from_layer  = conf->from_layer;
+        tm->to_layer    = conf->to_layer;
+        tm->config      = ts_conf;
+
+        m->datalen = sizeof(*tm);
+        m->data = (unsigned long) tm;
+
+        return 0;
+}
+
+static void em_text_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
+{
+        textsearch_destroy(EM_TEXT_PRIV(m)->config);
+}
+
+static int em_text_dump(struct sk_buff *skb, struct tcf_ematch *m)
+{
+        struct text_match *tm = EM_TEXT_PRIV(m);
+        struct tcf_em_text conf;
+
+        strncpy(conf.algo, tm->config->ops->name, sizeof(conf.algo) - 1);
+        conf.from_offset = tm->from_offset;
+        conf.to_offset = tm->to_offset;
+        conf.from_layer = tm->from_layer;
+        conf.to_layer = tm->to_layer;
+        conf.pattern_len = textsearch_get_pattern_len(tm->config);
+        conf.pad = 0;
+
+        RTA_PUT_NOHDR(skb, sizeof(conf), &conf);
+        RTA_APPEND(skb, conf.pattern_len, textsearch_get_pattern(tm->config));
+        return 0;
+
+rtattr_failure:
+        return -1;
+}               
+
+static struct tcf_ematch_ops em_text_ops = {
+        .kind     = TCF_EM_TEXT,
+        .change   = em_text_change,
+        .match    = em_text_match,
+        .destroy  = em_text_destroy,
+        .dump     = em_text_dump,
+        .owner    = THIS_MODULE,
+        .link     = LIST_HEAD_INIT(em_text_ops.link)
+};
+
+static int __init init_em_text(void)
+{
+        return tcf_em_register(&em_text_ops);
+}
+
+static void __exit exit_em_text(void) 
+{
+        tcf_em_unregister(&em_text_ops);
+}
+
+MODULE_LICENSE("GPL");
+
+module_init(init_em_text);
+module_exit(exit_em_text);