Wireshark · Wireshark-dev: Re: [Wireshark-dev] Multiple-line parsing of packets dissected over HTTP

[Pascal Quantin <pascal@xxxxxxxxxxxxx>]

Le mar. 19 janv. 2021 à 23:09, Joey Salazar <jgsal@xxxxxxxxxxxxxx> a écrit :

Hi Pascal,

On Tuesday, January 19, 2021 11:19 AM, Pascal Quantin wrote:

Hi Joey,

Le mar. 19 janv. 2021 à 17:45, Joey Salazar via Wireshark-dev <wireshark-dev@xxxxxxxxxxxxx> a écrit :

Hi all,

In commit 33af2649 [1] we can keep dissecting the contents of the req, adv, and res packets by setting

 while (plen > 0) { }

either in `dissect_git_pdu()` or in `dissect_one_pkt_line()`, but for now in `dissect_git_pdu()` it'd be a bit messy, so wanted to ask for your feedback for getting `dissect_one_pkt_line()` to work properly first.

As you can see in pcap 169 [2], it correctly parses the length of the first line as 0x0014 (20 bytes) until `0x0a`, then it's supposed to get the length of the next line by the first 4 hex bytes in that line, but instead of reading the length as 0x0018 (24 bytes) it's reading it as 0x0010 (16 bytes), and anyways, this particular line's length actually is 59 bytes.

Suggestions on how to approach this?

So what is the code leading to this dissection? It does not seem to be https://gitlab.com/joeysal/wireshark/-/commit/33af2649927cb5660d4aeb64b9a9e9a58a1823aa as dissect_one_pkt_line() seem to read only one line

Yes, the code on that commit is what gives the parsing of the screenshot.

So what mechanism is used to call dissect_one_plt_line() a second time? With only screenshots and no pcap / code to look at, we can hardly help. Does it mean that packet-http.c calls your dissector per line? Please provide more info, or even better share the pcap if you want us to provide some help.

Best regards.