ip_frag: add IPv4 options fragment and unit test data

Message ID 1637743626-70632-1-git-send-email-chcchc88@163.com (mailing list archive)
State Superseded, archived
Delegated to: David Marchand
Headers
Series ip_frag: add IPv4 options fragment and unit test data |

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Commit Message

Huichao Cai Nov. 24, 2021, 8:47 a.m. UTC
  According to RFC791,the options may appear or not in datagrams.
They must be implemented by all IP modules (host and gateways).
What is optional is their transmission in any particular datagram,
not their implementation.So we have to deal with it during the
fragmenting process.Add some test data for the IPv4 header optional
field fragmenting.

Signed-off-by: Huichao Cai <chcchc88@163.com>
---
 app/test/test_ipfrag.c               | 269 ++++++++++++++++++++++++++++++++---
 lib/ip_frag/rte_ipv4_fragmentation.c |  52 ++++++-
 2 files changed, 301 insertions(+), 20 deletions(-)
  

Comments

Dariusz Sosnowski Dec. 1, 2021, 11:49 a.m. UTC | #1
On Wed, 24 Nov 2021 16:47:06 +0800, Huichao Cai wrote:
> +/*
> + *     Options "fragmenting", just fill options not
> + *     allowed in fragments with NOOPs.
> + *     Simple and stupid 8), but the most efficient way.
> + */
> +static inline void ip_options_fragment(struct rte_ipv4_hdr *iph)
> +{
> +       unsigned char *optptr = (unsigned char *)iph +
> +           sizeof(struct rte_ipv4_hdr);
> +       int l = (iph->version_ihl & RTE_IPV4_HDR_IHL_MASK) *
> +           RTE_IPV4_IHL_MULTIPLIER - sizeof(struct rte_ipv4_hdr);
> +       int optlen;
> +
> +       while (l > 0) {
> +               switch (*optptr) {
> +               case RTE_IPOPT_END:
> +                       return;
> +               case RTE_IPOPT_NOOP:
> +                       l--;
> +                       optptr++;
> +                       continue;
> +               }
> +               optlen = optptr[1];
> +               if (optlen < 2 || optlen > l)
> +                       return;
> +               if (!RTE_IPOPT_COPIED(*optptr))
> +                       memset(optptr, RTE_IPOPT_NOOP, optlen);
> +               l -= optlen;
> +               optptr += optlen;
> +       }
> +}
> +
I have a few concerns regarding this implementation:
- Any IPv4 option longer than 2 bytes with copied flag unset, will not be substituted by NOOP option. In effect it will be copied to all fragments.
- Substituting options with NOOP might cause rte_ipv4_fragment_packet to produce more fragments than necessary, since options with copied flag unset will still occupy space in IPv4 header.
It would require some benchmarking, but maybe a better solution would be to prepare a separate IPv4 header for fragments without unnecessary options.
  
Huichao Cai Dec. 2, 2021, 2:24 a.m. UTC | #2
Hi Dariusz


Substituting options with NOOP might cause rte_ipv4_fragment_packet to produce more fragments than necessary, since options with copied flag unset will still occupy space in IPv4 header.


--The "ip_options_fragment" just make a replacement and doesn't change the length of the IPv4 header.So I don't quite understand why it leads to produce more fragments.


but maybe a better solution would be to prepare a separate IPv4 header for fragments without unnecessary options.
--Yes, we can do this, but it adds some extra work, such as generating a new IPv4 header and reassembling the data,which has some performance implications.

Huichao Cai
  

Patch

diff --git a/app/test/test_ipfrag.c b/app/test/test_ipfrag.c
index 1ced25a..ecb9426 100644
--- a/app/test/test_ipfrag.c
+++ b/app/test/test_ipfrag.c
@@ -18,10 +18,101 @@ 
 #define NUM_MBUFS 128
 #define BURST 32
 
+/* IP options */
+#define RTE_IPOPT_COPY				0x80
+#define RTE_IPOPT_CONTROL			0x00
+#define RTE_IPOPT_END				(0 | RTE_IPOPT_CONTROL)
+#define RTE_IPOPT_NOOP				(1 | RTE_IPOPT_CONTROL)
+#define RTE_IPOPT_COPIED(o)			((o) & RTE_IPOPT_COPY)
+#define RTE_IPOPT_MAX_LEN 40
+
+#define IPOPT_MANUAL
+
+#ifdef IPOPT_MANUAL
+uint8_t expected_first_frag_ipv4_opts[] = {
+	0x07, 0x0b, 0x04, 0x00,
+	0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x83,
+	0x07, 0x04, 0xc0, 0xa8,
+	0xe3, 0x96, 0x00, 0x00,
+};
+
+uint8_t expected_sub_frag_ipv4_opts[] = {
+	RTE_IPOPT_NOOP, RTE_IPOPT_NOOP, RTE_IPOPT_NOOP, RTE_IPOPT_NOOP,
+	RTE_IPOPT_NOOP, RTE_IPOPT_NOOP, RTE_IPOPT_NOOP, RTE_IPOPT_NOOP,
+	RTE_IPOPT_NOOP, RTE_IPOPT_NOOP, RTE_IPOPT_NOOP, 0x83,
+	0x07, 0x04, 0xc0, 0xa8,
+	0xe3, 0x96, 0x00, 0x00,
+};
+#else
+/**
+ * IPv4 Options
+ */
+struct test_ipv4_opt {
+	__extension__
+	union {
+		uint8_t type;		    /**< option type */
+		struct {
+#if RTE_BYTE_ORDER == RTE_LITTLE_ENDIAN
+			uint8_t number:5;   /**< option number */
+			uint8_t category:2; /**< option class */
+			uint8_t copied:1;   /**< option copy flag */
+#elif RTE_BYTE_ORDER == RTE_BIG_ENDIAN
+			uint8_t copied:1;   /**< option copy flag */
+			uint8_t category:2; /**< option class */
+			uint8_t number:5;   /**< option number */
+#endif
+		} s_type;
+	};
+	uint8_t length;			    /**< option length */
+	uint8_t pointer;		    /**< option pointer */
+	uint8_t data[37];		    /**< option data */
+} __rte_packed;
+
+struct test_ipv4_opt test_ipv4_opts[] = {
+	{
+		.s_type.copied = 0,
+		.s_type.category = 0,
+		.s_type.number = 7,
+		.length = 11,
+		.pointer = 4,
+	},
+	{
+		.s_type.copied = 1,
+		.s_type.category = 0,
+		.s_type.number = 3,
+		.length = 7,
+		.pointer = 4,
+		.data[0] = 0xc0,
+		.data[1] = 0xa8,
+		.data[2] = 0xe3,
+		.data[3] = 0x96,
+	},
+};
+#endif
+
+struct test_opt_data {
+	bool is_first_frag;		 /**< offset is 0 */
+	uint16_t len;			 /**< option data len */
+	uint8_t data[RTE_IPOPT_MAX_LEN]; /**< option data */
+};
+
 static struct rte_mempool *pkt_pool,
 			  *direct_pool,
 			  *indirect_pool;
 
+static inline void
+hex_to_str(uint8_t *hex, uint16_t len, char *str)
+{
+	int i;
+
+	for (i = 0; i < len; i++) {
+		sprintf(str, "%02x", hex[i]);
+		str += 2;
+	}
+	*str = 0;
+}
+
 static int
 setup_buf_pool(void)
 {
@@ -88,23 +179,78 @@  static void ut_teardown(void)
 {
 }
 
+static inline void
+test_get_ipv4_opt(bool is_first_frag,
+	struct test_opt_data *expected_opt)
+{
+#ifdef IPOPT_MANUAL
+	if (is_first_frag) {
+		expected_opt->len = sizeof(expected_first_frag_ipv4_opts);
+		rte_memcpy(expected_opt->data, expected_first_frag_ipv4_opts,
+			sizeof(expected_first_frag_ipv4_opts));
+	} else {
+		expected_opt->len = sizeof(expected_sub_frag_ipv4_opts);
+		rte_memcpy(expected_opt->data, expected_sub_frag_ipv4_opts,
+			sizeof(expected_sub_frag_ipv4_opts));
+	}
+#else
+	uint16_t i;
+	uint16_t pos = 0;
+	expected_opt->len = 0;
+
+	for (i = 0; i < RTE_DIM(test_ipv4_opts); i++) {
+		if (unlikely(pos + test_ipv4_opts[i].length >
+				RTE_IPOPT_MAX_LEN))
+			return;
+
+		if (is_first_frag) {
+			rte_memcpy(expected_opt->data + pos, &test_ipv4_opts[i],
+				test_ipv4_opts[i].length);
+		} else {
+			if (test_ipv4_opts[i].s_type.copied)
+				rte_memcpy(expected_opt->data + pos,
+					&test_ipv4_opts[i],
+					test_ipv4_opts[i].length);
+			else
+				memset(expected_opt->data + pos, RTE_IPOPT_NOOP,
+					test_ipv4_opts[i].length);
+		}
+		expected_opt->len += test_ipv4_opts[i].length;
+		pos += test_ipv4_opts[i].length;
+	}
+
+	expected_opt->len = RTE_ALIGN_CEIL(expected_opt->len, 4);
+	memset(expected_opt->data + pos, RTE_IPOPT_END,
+		expected_opt->len - pos);
+#endif
+}
+
 static void
-v4_allocate_packet_of(struct rte_mbuf *b, int fill,
-		      size_t s, int df, uint8_t mf, uint16_t off,
-		      uint8_t ttl, uint8_t proto, uint16_t pktid)
+v4_allocate_packet_of(struct rte_mbuf *b, int fill, size_t s,
+	int df, uint8_t mf, uint16_t off, uint8_t ttl, uint8_t proto,
+	uint16_t pktid, bool have_opt, bool is_first_frag)
 {
 	/* Create a packet, 2k bytes long */
 	b->data_off = 0;
 	char *data = rte_pktmbuf_mtod(b, char *);
-	rte_be16_t fragment_offset = 0;	/**< fragmentation offset */
+	rte_be16_t fragment_offset = 0;	/* fragmentation offset */
+	uint16_t iph_len;
+	struct test_opt_data opt;
 
-	memset(data, fill, sizeof(struct rte_ipv4_hdr) + s);
+	opt.len = 0;
+
+	if (have_opt)
+		test_get_ipv4_opt(is_first_frag, &opt);
+
+	iph_len = sizeof(struct rte_ipv4_hdr) + opt.len;
+	memset(data, fill, iph_len + s);
 
 	struct rte_ipv4_hdr *hdr = (struct rte_ipv4_hdr *)data;
 
-	hdr->version_ihl = 0x45; /* standard IP header... */
+	hdr->version_ihl = 0x40; /* ipv4 */
+	hdr->version_ihl += (iph_len / 4);
 	hdr->type_of_service = 0;
-	b->pkt_len = s + sizeof(struct rte_ipv4_hdr);
+	b->pkt_len = s + iph_len;
 	b->data_len = b->pkt_len;
 	hdr->total_length = rte_cpu_to_be_16(b->pkt_len);
 	hdr->packet_id = rte_cpu_to_be_16(pktid);
@@ -131,6 +277,8 @@  static void ut_teardown(void)
 	hdr->hdr_checksum = 0;
 	hdr->src_addr = rte_cpu_to_be_32(0x8080808);
 	hdr->dst_addr = rte_cpu_to_be_32(0x8080404);
+
+	rte_memcpy(hdr + 1, opt.data, opt.len);
 }
 
 static void
@@ -187,6 +335,43 @@  static void ut_teardown(void)
 	}
 }
 
+static inline void
+test_get_frag_opt(struct rte_mbuf **mb, int32_t num,
+	struct test_opt_data *opt, int ipv)
+{
+	int32_t i;
+
+	for (i = 0; i < num; i++) {
+		if (ipv == 4) {
+			struct rte_ipv4_hdr *iph =
+			    rte_pktmbuf_mtod(mb[i], struct rte_ipv4_hdr *);
+			uint16_t header_len = (iph->version_ihl &
+				RTE_IPV4_HDR_IHL_MASK) *
+				RTE_IPV4_IHL_MULTIPLIER;
+			uint16_t opt_len = header_len -
+				sizeof(struct rte_ipv4_hdr);
+
+			if ((rte_be_to_cpu_16(iph->fragment_offset) &
+				    RTE_IPV4_HDR_OFFSET_MASK) == 0)
+				opt->is_first_frag = true;
+			else
+				opt->is_first_frag = false;
+
+			if (opt_len && (opt_len <= RTE_IPOPT_MAX_LEN)) {
+				char *iph_opt = rte_pktmbuf_mtod_offset(mb[i],
+				    char *, sizeof(struct rte_ipv4_hdr));
+				opt->len = opt_len;
+				rte_memcpy(opt->data, iph_opt, opt_len);
+			} else {
+				opt->len = RTE_IPOPT_MAX_LEN;
+				memset(opt->data, RTE_IPOPT_END,
+				    sizeof(opt->data));
+			}
+			opt++;
+		}
+	}
+}
+
 static int
 test_ip_frag(void)
 {
@@ -206,32 +391,43 @@  static void ut_teardown(void)
 		uint16_t pkt_id;
 		int      expected_frags;
 		uint16_t expected_fragment_offset[BURST];
+		bool have_opt;
+		bool is_first_frag;
 	} tests[] = {
 		 {4, 1280, 1400, 0, 0, 0, 64, IPPROTO_ICMP, RND_ID,       2,
-		  {0x2000, 0x009D}},
+		  {0x2000, 0x009D}, 0},
 		 {4, 1280, 1400, 0, 0, 0, 64, IPPROTO_ICMP, 0,            2,
-		  {0x2000, 0x009D}},
+		  {0x2000, 0x009D}, 0},
 		 {4,  600, 1400, 0, 0, 0, 64, IPPROTO_ICMP, RND_ID,       3,
-		  {0x2000, 0x2048, 0x0090}},
+		  {0x2000, 0x2048, 0x0090}, 0},
 		 {4, 4, 1400, 0, 0, 0, 64, IPPROTO_ICMP, RND_ID,    -EINVAL},
 		 {4, 600, 1400, 1, 0, 0, 64, IPPROTO_ICMP, RND_ID, -ENOTSUP},
 		 {4, 600, 1400, 0, 0, 0, 0, IPPROTO_ICMP, RND_ID,         3,
-		  {0x2000, 0x2048, 0x0090}},
-		 {4, 68, 104, 0, 1, 13, 0, IPPROTO_ICMP, RND_ID,          3,
-		  {0x200D, 0x2013, 0x2019}},
+		  {0x2000, 0x2046, 0x008C}, 1, 1},
+		 /* The first fragment */
+		 {4, 68, 104, 0, 1, 0, 0, IPPROTO_ICMP, RND_ID,           5,
+		  {0x2000, 0x2003, 0x2006, 0x2009, 0x200C}, 1, 1},
+		 /* The middle fragment */
+		 {4, 68, 104, 0, 1, 13, 0, IPPROTO_ICMP, RND_ID,          5,
+		  {0x200D, 0x2010, 0x2013, 0x2016, 0x2019}, 1, 0},
+		 /* The last fragment */
+		 {4, 68, 104, 0, 0, 26, 0, IPPROTO_ICMP, RND_ID,          5,
+		  {0x201A, 0x201D, 0x2020, 0x2023, 0x0026}, 1, 0},
 
 		 {6, 1280, 1400, 0, 0, 0, 64, IPPROTO_ICMP, RND_ID,       2,
-		  {0x0001, 0x04D0}},
+		  {0x0001, 0x04D0}, 0},
 		 {6, 1300, 1400, 0, 0, 0, 64, IPPROTO_ICMP, RND_ID,       2,
-		  {0x0001, 0x04E0}},
+		  {0x0001, 0x04E0}, 0},
 		 {6, 4, 1400, 0, 0, 0, 64, IPPROTO_ICMP, RND_ID,    -EINVAL},
 		 {6, 1300, 1400, 0, 0, 0, 0, IPPROTO_ICMP, RND_ID,        2,
-		  {0x0001, 0x04E0}},
+		  {0x0001, 0x04E0}, 0},
 	};
 
 	for (i = 0; i < RTE_DIM(tests); i++) {
 		int32_t len = 0;
 		uint16_t fragment_offset[BURST];
+		struct test_opt_data opt_res[BURST];
+		struct test_opt_data opt_exp;
 		uint16_t pktid = tests[i].pkt_id;
 		struct rte_mbuf *pkts_out[BURST];
 		struct rte_mbuf *b = rte_pktmbuf_alloc(pkt_pool);
@@ -250,7 +446,9 @@  static void ut_teardown(void)
 					      tests[i].set_of,
 					      tests[i].ttl,
 					      tests[i].proto,
-					      pktid);
+					      pktid,
+					      tests[i].have_opt,
+					      tests[i].is_first_frag);
 		} else if (tests[i].ipv == 6) {
 			v6_allocate_packet_of(b, 0x41414141,
 					      tests[i].pkt_size,
@@ -275,17 +473,21 @@  static void ut_teardown(void)
 		if (len > 0) {
 			test_get_offset(pkts_out, len,
 			    fragment_offset, tests[i].ipv);
+			if (tests[i].have_opt)
+				test_get_frag_opt(pkts_out, len,
+					opt_res,
+					tests[i].ipv);
 			test_free_fragments(pkts_out, len);
 		}
 
-		printf("%zd: checking %d with %d\n", i, len,
+		printf("[check frag number]%zd: checking %d with %d\n", i, len,
 		       tests[i].expected_frags);
 		RTE_TEST_ASSERT_EQUAL(len, tests[i].expected_frags,
 				      "Failed case %zd.\n", i);
 
 		if (len > 0) {
 			for (j = 0; j < (size_t)len; j++) {
-				printf("%zd-%zd: checking %d with %d\n",
+				printf("[check offset]%zd-%zd: checking %d with %d\n",
 				    i, j, fragment_offset[j],
 				    rte_cpu_to_be_16(
 					tests[i].expected_fragment_offset[j]));
@@ -294,6 +496,35 @@  static void ut_teardown(void)
 					tests[i].expected_fragment_offset[j]),
 				    "Failed case %zd.\n", i);
 			}
+
+			if (tests[i].have_opt && (tests[i].ipv == 4)) {
+				for (j = 0; j < (size_t)len; j++) {
+					char opt_res_str[2 *
+						RTE_IPOPT_MAX_LEN + 1];
+					char opt_exp_str[2 *
+						RTE_IPOPT_MAX_LEN + 1];
+
+					test_get_ipv4_opt(
+						opt_res[j].is_first_frag,
+						&opt_exp);
+					hex_to_str(opt_res[j].data,
+						opt_res[j].len,
+						opt_res_str);
+					hex_to_str(opt_exp.data,
+						opt_exp.len,
+						opt_exp_str);
+
+					printf(
+						"[check ipv4 option]%zd-%zd: checking (%u)%s with (%u)%s\n",
+						i, j,
+						opt_res[j].len, opt_res_str,
+						opt_exp.len, opt_exp_str);
+						RTE_TEST_ASSERT_SUCCESS(
+							strcmp(opt_res_str,
+								opt_exp_str),
+						"Failed case %zd.\n", i);
+				}
+			}
 		}
 
 	}
diff --git a/lib/ip_frag/rte_ipv4_fragmentation.c b/lib/ip_frag/rte_ipv4_fragmentation.c
index 2e7739d..bcafa29 100644
--- a/lib/ip_frag/rte_ipv4_fragmentation.c
+++ b/lib/ip_frag/rte_ipv4_fragmentation.c
@@ -1,4 +1,4 @@ 
-/* SPDX-License-Identifier: BSD-3-Clause
+/* SPDX-License-Identifier: (BSD-3-Clause OR GPL-2.0)
  * Copyright(c) 2010-2014 Intel Corporation
  */
 
@@ -12,6 +12,13 @@ 
 
 #include "ip_frag_common.h"
 
+/* IP options */
+#define RTE_IPOPT_COPY				0x80
+#define RTE_IPOPT_CONTROL			0x00
+#define RTE_IPOPT_END				(0 | RTE_IPOPT_CONTROL)
+#define RTE_IPOPT_NOOP				(1 | RTE_IPOPT_CONTROL)
+#define RTE_IPOPT_COPIED(o)			((o) & RTE_IPOPT_COPY)
+
 /* Fragment Offset */
 #define	RTE_IPV4_HDR_DF_SHIFT			14
 #define	RTE_IPV4_HDR_MF_SHIFT			13
@@ -41,6 +48,38 @@  static inline void __free_fragments(struct rte_mbuf *mb[], uint32_t num)
 		rte_pktmbuf_free(mb[i]);
 }
 
+/*
+ *	Options "fragmenting", just fill options not
+ *	allowed in fragments with NOOPs.
+ *	Simple and stupid 8), but the most efficient way.
+ */
+static inline void ip_options_fragment(struct rte_ipv4_hdr *iph)
+{
+	unsigned char *optptr = (unsigned char *)iph +
+	    sizeof(struct rte_ipv4_hdr);
+	int l = (iph->version_ihl & RTE_IPV4_HDR_IHL_MASK) *
+	    RTE_IPV4_IHL_MULTIPLIER - sizeof(struct rte_ipv4_hdr);
+	int optlen;
+
+	while (l > 0) {
+		switch (*optptr) {
+		case RTE_IPOPT_END:
+			return;
+		case RTE_IPOPT_NOOP:
+			l--;
+			optptr++;
+			continue;
+		}
+		optlen = optptr[1];
+		if (optlen < 2 || optlen > l)
+			return;
+		if (!RTE_IPOPT_COPIED(*optptr))
+			memset(optptr, RTE_IPOPT_NOOP, optlen);
+		l -= optlen;
+		optptr += optlen;
+	}
+}
+
 /**
  * IPv4 fragmentation.
  *
@@ -188,6 +227,17 @@  static inline void __free_fragments(struct rte_mbuf *mb[], uint32_t num)
 		    (uint16_t)out_pkt->pkt_len,
 		    flag_offset, fragment_offset, more_in_segs);
 
+		/*
+		 * ANK: dirty, but effective trick. Upgrade options only if
+		 * the segment to be fragmented was THE FIRST (otherwise,
+		 * options are already fixed) and make it ONCE
+		 * on the initial mbuf, so that all the following fragments
+		 * will inherit fixed options.
+		 */
+		if ((fragment_offset == 0) &&
+			    ((flag_offset & RTE_IPV4_HDR_OFFSET_MASK) == 0))
+			ip_options_fragment(in_hdr);
+
 		fragment_offset = (uint16_t)(fragment_offset +
 		    out_pkt->pkt_len - header_len);