Date:	Fri, 4 Mar 2016 15:39:23 +0000
From:	Brian Russell <brian.russell@...cade.com>
To:	Joe Perches <joe@...ches.com>, <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next v3 2/3] nsh: logging module



On 01/03/16 18:25, Joe Perches wrote:
> On Tue, 2016-03-01 at 11:11 +0000, Brian Russell wrote:
>> Module can register for Type 1 or specified classes of Type 2 metadata
>> and will then log incoming matching packets.
> 
> This logging mechanism seems like a way to fill/DoS logs.
> 
> Maybe use pr_info_ratelimit?
> Maybe use the trace_events mechanisms instead?
> 

Thanks, will do.

Brian

>> Signed-off-by: Brian Russell <brussell@...cade.com>
>> ---
>>  net/ipv4/Kconfig   |   8 ++++
>>  net/ipv4/Makefile  |   1 +
>>  net/ipv4/nsh_log.c | 135 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 144 insertions(+)
>>  create mode 100644 net/ipv4/nsh_log.c
>>
>> diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
>> index df14c59..87b6dde 100644
>> --- a/net/ipv4/Kconfig
>> +++ b/net/ipv4/Kconfig
>> @@ -223,6 +223,14 @@ config NET_NSH
>>  
>>            To compile it as a module, choose M here.  If unsure, say N.
>>  
>> +config NET_NSH_LOG
>> +        tristate 'NSH Metadata Logger'
>> +	depends on NET_NSH
>> +	help
>> +          Log packets with incoming NSH metadata.
>> +
>> +          To compile it as a module, choose M here.  If unsure, say N.
>> +
>>  config IP_MROUTE
>>  	bool "IP: multicast routing"
>>  	depends on IP_MULTICAST
>> diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
>> index 14b7995..69377fb 100644
>> --- a/net/ipv4/Makefile
>> +++ b/net/ipv4/Makefile
>> @@ -25,6 +25,7 @@ obj-$(CONFIG_NET_FOU) += fou.o
>>  obj-$(CONFIG_NET_IPGRE_DEMUX) += gre.o
>>  obj-$(CONFIG_NET_IPGRE) += ip_gre.o
>>  obj-$(CONFIG_NET_NSH) += nsh.o
>> +obj-$(CONFIG_NET_NSH_LOG) += nsh_log.o
>>  obj-$(CONFIG_NET_UDP_TUNNEL) += udp_tunnel.o
>>  obj-$(CONFIG_NET_IPVTI) += ip_vti.o
>>  obj-$(CONFIG_SYN_COOKIES) += syncookies.o
>> diff --git a/net/ipv4/nsh_log.c b/net/ipv4/nsh_log.c
>> new file mode 100644
>> index 0000000..3d774ed
>> --- /dev/null
>> +++ b/net/ipv4/nsh_log.c
>> @@ -0,0 +1,135 @@
>> +/*
>> + * Network Service Header (NSH) logging module.
>> + *
>> + * Copyright (c) 2016 by Brocade Communications Systems, Inc.
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + */
>> +#include 
>> +#include 
>> +#include 
>> +
>> +static bool t1_enabled = false;
>> +module_param(t1_enabled, bool, 0444);
>> +MODULE_PARM_DESC(t1_enabled, "Type 1 Metadata log enabled");
>> +
>> +#define MAX_T2_CLASSES 10
>> +static unsigned int t2_classes[MAX_T2_CLASSES];
>> +static int num_t2 = 0;
>> +module_param_array(t2_classes, uint, &num_t2, 0444);
>> +MODULE_PARM_DESC(t2_classes, "Type 2 Metadata classes log enabled");
>> +
>> +static const char *nsh_next_proto(u8 next_proto)
>> +{
>> +	switch (next_proto) {
>> +	case NSH_NEXT_PROTO_IPv4:
>> +		return "IPv4";
>> +	case NSH_NEXT_PROTO_IPv6:
>> +		return "IPv6";
>> +	case NSH_NEXT_PROTO_ETH:
>> +		return "Eth";
>> +	default:
>> +		return "Unknown";
>> +	}
>> +}
>> +
>> +/* Type 1 metadata has fixed length, 4 x 32-bit words */
>> +static int nsh_log_t1(struct sk_buff *skb, u32 service_path_id,
>> +		      u8 service_index, u8 next_proto,
>> +		      struct nsh_metadata *ctx_hdr, unsigned int num_ctx_hdrs)
>> +{
>> +	u32 *data;
>> +
>> +	if ((ctx_hdr->class != NSH_MD_CLASS_TYPE_1) ||
>> +	    (ctx_hdr->type != NSH_MD_TYPE_TYPE_1) ||
>> +	    (ctx_hdr->len != NSH_MD_LEN_TYPE_1) ||
>> +	    (num_ctx_hdrs != 1))
>> +		return -EINVAL;
>> +
>> +	data = ctx_hdr->data;
>> +	pr_info("NSH T1 Rx(%s): SPI=%u SI=%u Next=%s"
>> +		" MD 0x%08x 0x%08x 0x%08x 0x%08x\n", skb->dev->name,
>> +		service_path_id, service_index, nsh_next_proto(next_proto),
>> +		data[0], data[1], data[2], data[3]);
>> +
>> +	return 0;
>> +}
>> +
>> +/* Type 2 metadata consists of a variable number of TLVs */
>> +#define T2_BUFSIZE 512
>> +static int nsh_log_t2(struct sk_buff *skb, u32 service_path_id,
>> +		      u8 service_index, u8 next_proto,
>> +		      struct nsh_metadata *ctx_hdrs, unsigned int num_ctx_hdrs)
>> +{
>> +	char t2_buf[T2_BUFSIZE];
>> +	int wrlen;
>> +	u32 *data;
>> +	int i,j;
>> +
>> +	wrlen = snprintf(t2_buf, T2_BUFSIZE,
>> +			 "NSH T2 Class %u Rx(%s): SPI=%u SI=%u Next=%s MD",
>> +			 ctx_hdrs[0].class, skb->dev->name, service_path_id,
>> +			 service_index, nsh_next_proto(next_proto));
>> +
>> +	for (i = 0; i < num_ctx_hdrs; i++) {
>> +		wrlen += snprintf(t2_buf+wrlen, T2_BUFSIZE-wrlen,
>> +				  " TLV%d Type=%u Len=%u", i+1,
>> +				  ctx_hdrs[i].type, ctx_hdrs[i].len);
>> +		data = ctx_hdrs[i].data;
>> +		for (j = 0; j < ctx_hdrs[i].len; j++)
>> +			wrlen += snprintf(t2_buf+wrlen, T2_BUFSIZE-wrlen,
>> +					  " 0x%08x", data[j]);
>> +	}
>> +	pr_info("%s\n", t2_buf);
>> +	return 0;
>> +}
>> +
>> +static struct nsh_listener nsh_log_t1_entry = {
>> +	.class = NSH_MD_CLASS_TYPE_1,
>> +	.notify = nsh_log_t1,
>> +};
>> +
>> +static struct nsh_listener nsh_log_t2_entry[MAX_T2_CLASSES];
>> +
>> +static int __init nsh_log_init(void)
>> +{
>> +	int i, err;
>> +
>> +	if (t1_enabled) {
>> +		err = nsh_register_listener(&nsh_log_t1_entry);
>> +
>> +		if (err)
>> +			return err;
>> +	}
>> +
>> +	for (i = 0; i < num_t2; i++) {
>> +		nsh_log_t2_entry[i].class = t2_classes[i];
>> +		nsh_log_t2_entry[i].notify = nsh_log_t2;
>> +
>> +		err = nsh_register_listener(&nsh_log_t2_entry[i]);
>> +
>> +		if (err)
>> +			return err;
>> +	}
>> +	return 0;
>> +}
>> +
>> +static void __exit nsh_log_exit(void)
>> +{
>> +	int i;
>> +
>> +	if (t1_enabled)
>> +		nsh_unregister_listener(&nsh_log_t1_entry);
>> +
>> +	for (i = 0; i < num_t2; i++)
>> +		nsh_unregister_listener(&nsh_log_t2_entry[i]);
>> +}
>> +
>> +module_init(nsh_log_init);
>> +module_exit(nsh_log_exit);
>> +
>> +MODULE_LICENSE("GPL");
>> +MODULE_AUTHOR("Brian Russell <brussell@...cade.com>");
>> +MODULE_DESCRIPTION("NSH Metadata logger");
> 

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