diff mbox series

net: calculate checksums for packets with IPv4 options

Message ID 20200821113210.307175-1-michael.pfeiffer@tu-ilmenau.de (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers show
Series net: calculate checksums for packets with IPv4 options | expand

Checks

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

Commit Message

Michael Pfeiffer Aug. 21, 2020, 11:32 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>
---
 lib/librte_net/rte_ip.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

Comments

Andrew Rybchenko Aug. 29, 2020, 11:43 a.m. UTC | #1
On 8/21/20 2:32 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>
> ---
>  lib/librte_net/rte_ip.h | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/librte_net/rte_ip.h b/lib/librte_net/rte_ip.h
> index fcd1eb342..6c3ff2603 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;
>  }
>  
> @@ -311,7 +311,7 @@ rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr *ipv4_hdr, uint64_t ol_flags)
>  	} 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)));
> +				- ((ipv4_hdr->version_ihl & 0xf) * 4)));
>  	}
>  	return rte_raw_cksum(&psd_hdr, sizeof(psd_hdr));
>  }
> @@ -319,8 +319,8 @@ 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.
> @@ -339,7 +339,7 @@ rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr)
>  	if (l3_len < sizeof(struct rte_ipv4_hdr))
>  		return 0;
>  
> -	l4_len = l3_len - sizeof(struct rte_ipv4_hdr);
> +	l4_len = l3_len - ((ipv4_hdr->version_ihl & 0xf) * 4);

Previous if condition guarantees that the result will be not
negative (and make huge l4_len), so it looks like it should be
updated as well. I think it makes sense to introduce
additional variable with calculated IPv4 header length.

>  
>  	cksum = rte_raw_cksum(l4_hdr, l4_len);
>  	cksum += rte_ipv4_phdr_cksum(ipv4_hdr, 0);
>
diff mbox series

Patch

diff --git a/lib/librte_net/rte_ip.h b/lib/librte_net/rte_ip.h
index fcd1eb342..6c3ff2603 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;
 }
 
@@ -311,7 +311,7 @@  rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr *ipv4_hdr, uint64_t ol_flags)
 	} 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)));
+				- ((ipv4_hdr->version_ihl & 0xf) * 4)));
 	}
 	return rte_raw_cksum(&psd_hdr, sizeof(psd_hdr));
 }
@@ -319,8 +319,8 @@  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.
@@ -339,7 +339,7 @@  rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr)
 	if (l3_len < sizeof(struct rte_ipv4_hdr))
 		return 0;
 
-	l4_len = l3_len - sizeof(struct rte_ipv4_hdr);
+	l4_len = l3_len - ((ipv4_hdr->version_ihl & 0xf) * 4);
 
 	cksum = rte_raw_cksum(l4_hdr, l4_len);
 	cksum += rte_ipv4_phdr_cksum(ipv4_hdr, 0);