diff mbox series

[v2] net: calculate checksums for packets with IPv4 options

Message ID 20200901094755.561661-1-michael.pfeiffer@tu-ilmenau.de (mailing list archive)
State Accepted, archived
Delegated to: Thomas Monjalon
Headers
Series [v2] net: calculate checksums for packets with IPv4 options |

Checks

Context Check Description
ci/iol-testing success Testing PASS
ci/iol-mellanox-Performance success Performance Testing PASS
ci/travis-robot success Travis build: passed
ci/Intel-compilation success Compilation OK
ci/checkpatch success coding style OK

Commit Message

Michael Pfeiffer Sept. 1, 2020, 9:47 a.m. UTC 
  Currently, rte_ipv4_cksum() and rte_ipv4_udptcp_cksum() assume all IPv4
headers have sizeof(struct rte_ipv4_hdr) bytes. This is not true for
those (rare) packets with IPv4 options. Thus, both IPv4 and TCP/UDP
checksums are calculated wrong.

This patch fixes the issue by using the actual IPv4 header length from
the packet's IHL field.

Signed-off-by: Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>
---
v2:
* Use actual header length for sanity check as well.
* Introduce ip_hdr_len variable to increase readability.

 lib/librte_net/rte_ip.h | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

Comments

Andrew Rybchenko Sept. 7, 2020, 7:48 a.m. UTC | #1 
On 9/1/20 12:47 PM, Michael Pfeiffer wrote:
> Currently, rte_ipv4_cksum() and rte_ipv4_udptcp_cksum() assume all IPv4
> headers have sizeof(struct rte_ipv4_hdr) bytes. This is not true for
> those (rare) packets with IPv4 options. Thus, both IPv4 and TCP/UDP
> checksums are calculated wrong.
> 
> This patch fixes the issue by using the actual IPv4 header length from
> the packet's IHL field.
> 
> Signed-off-by: Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>

Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>
Thomas Monjalon Oct. 5, 2020, 10:55 p.m. UTC | #2 
> -       cksum = rte_raw_cksum(ipv4_hdr, sizeof(struct rte_ipv4_hdr));
> +       cksum = rte_raw_cksum(ipv4_hdr, (ipv4_hdr->version_ihl & 0xf) * 4);

Truly naive questions:
- doesn't it deserve a static inline function rte_ipv4_hdr_len()?
- how generated code for "* 4" compares with "<< 2"?
Stephen Hemminger Oct. 6, 2020, 2:39 a.m. UTC | #3 
On Tue, 06 Oct 2020 00:55:19 +0200
Thomas Monjalon <thomas@monjalon.net> wrote:

> > -       cksum = rte_raw_cksum(ipv4_hdr, sizeof(struct rte_ipv4_hdr));
> > +       cksum = rte_raw_cksum(ipv4_hdr, (ipv4_hdr->version_ihl & 0xf) * 4);  
> 
> Truly naive questions:
> - doesn't it deserve a static inline function rte_ipv4_hdr_len()?

Makes sense to have that.

> - how generated code for "* 4" compares with "<< 2"?

The code is the same if value is unsigned.
Olivier Matz Oct. 6, 2020, 8:10 a.m. UTC | #4 
On Mon, Oct 05, 2020 at 07:39:45PM -0700, Stephen Hemminger wrote:
> On Tue, 06 Oct 2020 00:55:19 +0200
> Thomas Monjalon <thomas@monjalon.net> wrote:
> >
> > On 9/1/20 12:47 PM, Michael Pfeiffer wrote:
> > > Currently, rte_ipv4_cksum() and rte_ipv4_udptcp_cksum() assume all IPv4
> > > headers have sizeof(struct rte_ipv4_hdr) bytes. This is not true for
> > > those (rare) packets with IPv4 options. Thus, both IPv4 and TCP/UDP
> > > checksums are calculated wrong.
> > >
> > > This patch fixes the issue by using the actual IPv4 header length from
> > > the packet's IHL field.
> > >
> > > Signed-off-by: Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>

Acked-by: Olivier Matz <olivier.matz@6wind.com>

> > > -       cksum = rte_raw_cksum(ipv4_hdr, sizeof(struct rte_ipv4_hdr));
> > > +       cksum = rte_raw_cksum(ipv4_hdr, (ipv4_hdr->version_ihl & 0xf) * 4);
> >
> > Truly naive questions:
> > - doesn't it deserve a static inline function rte_ipv4_hdr_len()?
>
> Makes sense to have that.

+1

However it could be in another patch: there are ~15 places where it
could be replaced in dpdk.
Michael Pfeiffer Oct. 6, 2020, 9:51 a.m. UTC | #5 
Hi,

On Tue, 2020-10-06 at 10:10 +0200, Olivier Matz wrote:
> On Mon, Oct 05, 2020 at 07:39:45PM -0700, Stephen Hemminger wrote:
> > On Tue, 06 Oct 2020 00:55:19 +0200
> > Thomas Monjalon <thomas@monjalon.net> wrote:
> > > 
> > > On 9/1/20 12:47 PM, Michael Pfeiffer wrote:
> > > > Currently, rte_ipv4_cksum() and rte_ipv4_udptcp_cksum() assume all IPv4
> > > > headers have sizeof(struct rte_ipv4_hdr) bytes. This is not true for
> > > > those (rare) packets with IPv4 options. Thus, both IPv4 and TCP/UDP
> > > > checksums are calculated wrong.
> > > > 
> > > > This patch fixes the issue by using the actual IPv4 header length from
> > > > the packet's IHL field.
> > > > 
> > > > Signed-off-by: Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>
> 
> Acked-by: Olivier Matz <olivier.matz@6wind.com>
> 
> > > > -       cksum = rte_raw_cksum(ipv4_hdr, sizeof(struct rte_ipv4_hdr));
> > > > +       cksum = rte_raw_cksum(ipv4_hdr, (ipv4_hdr->version_ihl & 0xf) *
> > > > 4);
> > > 
> > > Truly naive questions:
> > > - doesn't it deserve a static inline function rte_ipv4_hdr_len()?
> > 
> > Makes sense to have that.
> 
> +1
> 
> However it could be in another patch: there are ~15 places where it
> could be replaced in dpdk.

Thank you very much for your feedback. I will prepare a second patch for that
function.
Thomas Monjalon Oct. 6, 2020, 3:10 p.m. UTC | #6 
06/10/2020 10:10, Olivier Matz:
> On Mon, Oct 05, 2020 at 07:39:45PM -0700, Stephen Hemminger wrote:
> > On Tue, 06 Oct 2020 00:55:19 +0200
> > Thomas Monjalon <thomas@monjalon.net> wrote:
> > >
> > > On 9/1/20 12:47 PM, Michael Pfeiffer wrote:
> > > > Currently, rte_ipv4_cksum() and rte_ipv4_udptcp_cksum() assume all IPv4
> > > > headers have sizeof(struct rte_ipv4_hdr) bytes. This is not true for
> > > > those (rare) packets with IPv4 options. Thus, both IPv4 and TCP/UDP
> > > > checksums are calculated wrong.
> > > >
> > > > This patch fixes the issue by using the actual IPv4 header length from
> > > > the packet's IHL field.
> > > >
> > > > Signed-off-by: Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>
> 
> Acked-by: Olivier Matz <olivier.matz@6wind.com>

Applied, thanks


> > > - doesn't it deserve a static inline function rte_ipv4_hdr_len()?
> >
> > Makes sense to have that.
> 
> +1
> 
> However it could be in another patch: there are ~15 places where it
> could be replaced in dpdk.

OK thanks for working on the improvement.
diff mbox series

Patch

diff --git a/lib/librte_net/rte_ip.h b/lib/librte_net/rte_ip.h
index fcd1eb342..bb55ebb6f 100644
--- a/lib/librte_net/rte_ip.h
+++ b/lib/librte_net/rte_ip.h
@@ -269,7 +269,7 @@  static inline uint16_t
 rte_ipv4_cksum(const struct rte_ipv4_hdr *ipv4_hdr)
 {
 	uint16_t cksum;
-	cksum = rte_raw_cksum(ipv4_hdr, sizeof(struct rte_ipv4_hdr));
+	cksum = rte_raw_cksum(ipv4_hdr, (ipv4_hdr->version_ihl & 0xf) * 4);
 	return (uint16_t)~cksum;
 }
 
@@ -302,6 +302,9 @@  rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr *ipv4_hdr, uint64_t ol_flags)
 		uint16_t len;      /* L4 length. */
 	} psd_hdr;
 
+	uint32_t l3_len;
+	uint8_t ip_hdr_len;
+
 	psd_hdr.src_addr = ipv4_hdr->src_addr;
 	psd_hdr.dst_addr = ipv4_hdr->dst_addr;
 	psd_hdr.zero = 0;
@@ -309,9 +312,9 @@  rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr *ipv4_hdr, uint64_t ol_flags)
 	if (ol_flags & PKT_TX_TCP_SEG) {
 		psd_hdr.len = 0;
 	} else {
-		psd_hdr.len = rte_cpu_to_be_16(
-			(uint16_t)(rte_be_to_cpu_16(ipv4_hdr->total_length)
-				- sizeof(struct rte_ipv4_hdr)));
+		l3_len = rte_be_to_cpu_16(ipv4_hdr->total_length);
+		ip_hdr_len = (ipv4_hdr->version_ihl & 0xf) * 4;
+		psd_hdr.len = rte_cpu_to_be_16((uint16_t)(l3_len - ip_hdr_len));
 	}
 	return rte_raw_cksum(&psd_hdr, sizeof(psd_hdr));
 }
@@ -319,8 +322,8 @@  rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr *ipv4_hdr, uint64_t ol_flags)
 /**
  * Process the IPv4 UDP or TCP checksum.
  *
- * The IPv4 header should not contains options. The IP and layer 4
- * checksum must be set to 0 in the packet by the caller.
+ * The IP and layer 4 checksum must be set to 0 in the packet by
+ * the caller.
  *
  * @param ipv4_hdr
  *   The pointer to the contiguous IPv4 header.
@@ -334,12 +337,14 @@  rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr)
 {
 	uint32_t cksum;
 	uint32_t l3_len, l4_len;
+	uint8_t ip_hdr_len;
 
+	ip_hdr_len = (ipv4_hdr->version_ihl & 0xf) * 4;
 	l3_len = rte_be_to_cpu_16(ipv4_hdr->total_length);
-	if (l3_len < sizeof(struct rte_ipv4_hdr))
+	if (l3_len < ip_hdr_len)
 		return 0;
 
-	l4_len = l3_len - sizeof(struct rte_ipv4_hdr);
+	l4_len = l3_len - ip_hdr_len;
 
 	cksum = rte_raw_cksum(l4_hdr, l4_len);
 	cksum += rte_ipv4_phdr_cksum(ipv4_hdr, 0);