Implement IPv4 checksum and use inverse maps for ethernet sculpting #74

aadilshabier · 2024-07-13T17:54:27Z

No description provided.

- Implement checksum calculation for IPv4 header. - Replace TOS header field with the new DSCP and ECN fields as directed in RFC 2474 and RFC 3168. Signed-off-by: Mohammad Aadil Shabier <aadilshabier1@gmail.com>

gabhijit

Mostly looks okay - I have not looked at the ipv4 checksum algorithm. Just assuming it's correct. Probably a good idea to add some test case for that.

Few other small changes.

src/layers/ethernet/mod.rs

src/types/ethertype.rs

This will be used when sculpting to select an EtherType based on the upcoming layer. Signed-off-by: Mohammad Aadil Shabier <aadilshabier1@gmail.com>

gabhijit · 2024-07-31T01:03:48Z

@aadilshabier: Sorry - This somehow got missed! Will take a look at it sometime soon (this week).

gabhijit

Mostly nitpicks: but are useful to get it right, so that we can merge it.

gabhijit · 2024-07-31T02:19:41Z

src/layers/arp.rs

@@ -14,7 +14,9 @@ pub const ARP_HEADER_LENGTH: usize = 28_usize;

 // Register outselves with Ethernet layer
 pub(crate) fn register_defaults() -> Result<(), Error> {
-    ethernet::register_ethertype(ETHERTYPE_ARP, ARP::creator)
+    let name = Some(ARP::default().name());


Use short_name (short_name is convenient and usually all lowercase)

gabhijit · 2024-07-31T02:22:05Z

src/layers/ethernet/mod.rs

    ETHERTYPES_MAP.get_or_init(|| RwLock::new(HashMap::new()))
 }

+/// A Map maintaining String -> EtherType of L3 Layers.


Add more description for the map as a documentation. If we simply read this documentation it is not clear why this map exists and how it is to be used. For example something like this.

/// This map will be used during sculpting a packet. For example for IPv4 you the entry /// in the map will look like `ip -> 0x0800`

gabhijit · 2024-07-31T02:23:35Z

src/layers/ethernet/mod.rs

    ETHERTYPES_MAP.get_or_init(|| RwLock::new(HashMap::new()))
 }

+/// A Map maintaining String -> EtherType of L3 Layers.
+pub fn get_inv_ethertypes_map() -> &'static RwLock<HashMap<String, EtherType>> {


May be this function is gated by cfg(packet_sculpting) ? Because this map and API is not used outside sculpting.

gabhijit · 2024-07-31T02:25:34Z

src/layers/ethernet/mod.rs

+
+    if let Some(name) = name {
+        let mut inv_map = get_inv_ethertypes_map().write().unwrap();
+        if inv_map.contains_key(name) {


if inv_map.contains_key(&name.to_lowercase())

gabhijit · 2024-07-31T02:26:47Z

src/layers/ethernet/mod.rs

+        let mut inv_map = get_inv_ethertypes_map().write().unwrap();
+        if inv_map.contains_key(name) {
+            return Err(Error::RegisterError(format!(
+                "Cannot find EtherType for : {}",


Error should be Already Exists and not cannot find. Also Better to let the user know what value exists in the inv_ map. So may be get and check for Some value?

gabhijit · 2024-07-31T02:27:53Z

src/layers/ipv4.rs

-
-    register_ethertype(crate::types::ETHERTYPE_IP, IPv4::creator)?;
-
+    let name = Some(IPv4::default().name());


short_name as above in ARP.

gabhijit · 2024-07-31T02:28:59Z

src/layers/ipv6.rs

@@ -26,8 +25,8 @@ fn get_next_headers_map() -> &'static RwLock<HashMap<u8, LayerCreatorFn>> {
 pub(crate) fn register_defaults() -> Result<(), Error> {
    use crate::layers::ethernet::register_ethertype;

-    get_next_headers_map();
-    register_ethertype(crate::types::ETHERTYPE_IP6, IPv6::creator)?;
+    let name = Some(IPv6::default().name());


short_name

gabhijit · 2024-07-31T02:29:18Z

src/layers/mpls.rs

@@ -16,8 +16,10 @@ pub const MPLS_HEADER_LENGTH: usize = 4_usize;

 // Register Ourselves to the Ethernet layer, as this is a 2.5 layer protocol
 pub(crate) fn register_defaults() -> Result<(), Error> {
-    ethernet::register_ethertype(ETHERTYPE_MPLS_UNICAST, MPLS::creator)?;
-    ethernet::register_ethertype(ETHERTYPE_MPLS_MULTICAST, MPLS::creator)
+    let name = Some(MPLS::default().name());


short_name

Implement IPv4 checksum and update header fields

8111765

- Implement checksum calculation for IPv4 header. - Replace TOS header field with the new DSCP and ECN fields as directed in RFC 2474 and RFC 3168. Signed-off-by: Mohammad Aadil Shabier <aadilshabier1@gmail.com>

aadilshabier force-pushed the sculpting branch from 6e42eec to 75c636c Compare July 13, 2024 17:55

gabhijit reviewed Jul 17, 2024

View reviewed changes

src/layers/ethernet/mod.rs Show resolved Hide resolved

src/layers/ethernet/mod.rs Show resolved Hide resolved

src/types/ethertype.rs Outdated Show resolved Hide resolved

Create inverse map from layer name to EtherType

7823c46

This will be used when sculpting to select an EtherType based on the upcoming layer. Signed-off-by: Mohammad Aadil Shabier <aadilshabier1@gmail.com>

aadilshabier force-pushed the sculpting branch from 75c636c to 7823c46 Compare July 20, 2024 08:02

aadilshabier changed the title ~~Implement IPv4 checksum and use inverse maps for ethernet scultping~~ Implement IPv4 checksum and use inverse maps for ethernet sculpting Jul 25, 2024

aadilshabier marked this pull request as ready for review July 29, 2024 14:26

gabhijit reviewed Jul 31, 2024

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Implement IPv4 checksum and use inverse maps for ethernet sculpting #74

Implement IPv4 checksum and use inverse maps for ethernet sculpting #74

aadilshabier commented Jul 13, 2024

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gabhijit commented Jul 31, 2024

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gabhijit Jul 31, 2024

gabhijit Jul 31, 2024

gabhijit Jul 31, 2024

gabhijit Jul 31, 2024

gabhijit Jul 31, 2024

gabhijit Jul 31, 2024

gabhijit Jul 31, 2024

gabhijit Jul 31, 2024


		register_ethertype(crate::types::ETHERTYPE_IP, IPv4::creator)?;

		let name = Some(IPv4::default().name());

Implement IPv4 checksum and use inverse maps for ethernet sculpting #74

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