RTSP: Trim whitespace from CSeq header before parsing

[nemosupremo]

Working with Longse (also may share the same software/firmware with Herospeed) cameras we found that Retina was unable to communicate with these cameras. Upon analyzing the packets, we saw that these cameras were adding a space after the Cseq header value (So instead of Cseq: 101\r\n, we saw Cseq: 101 \r\n).

This PR simply adds a trim method before the Cseq is parsed so that these cameras can be supported successfully.

longse.pkt.zip

[scottlamb]

Thanks for the report and packet capture!

I wonder if we should handle this in the rtsp-types layer for all headers. RTSP/1.0 RFC 2636 section 4.1 refers to HTTP/1.1 RFC 2068 section 4.1 which is not very clear about if trailing whitespace should be stripped.

          message-header = field-name ":" [ field-value ] CRLF

          field-name     = token
          field-value    = *( field-content | LWS )

          field-content  = <the OCTETs making up the field-value
                           and consisting of either *TEXT or combinations
                           of token, tspecials, and quoted-string>

but the HTTP/1.1 RFCs have since been updated/clarified. RFC 9110 explicitly says the following:

A field value does not include leading or trailing whitespace. When a specific version of HTTP allows such whitespace to appear in a message, a field parsing implementation MUST exclude such whitespace prior to evaluating the field value.

Would you like to file a rtsp-types issue about this? If not, I can.

Regardless of whether we fix this in retina or rtsp-types, I'd like to add a unit test of this scenario also.

[nemosupremo]

I see, the RFC is pretty explicit so it seems the issue lies with sdroege/rtsp-types; for completeness (there might be other headers) it makes sense to fix the issue there.

[nemosupremo]

Closing this PR as the solution has been implemented in sdroege/rtsp-types 0.0.5

[scottlamb]

I'll prep a new Retina release. For whatever reason rtsp-types releases have been 0.0.z, and according to cargo's rules:

"0.0.z" releases are always major changes.

so retina's Cargo.toml has to change to pick it up.

[scottlamb]

0.4.5 released.