_http3_header_field Struct Reference

Public Attributes
struct {
unsigned   len
unsigned   offset
}	encoded
struct {
const char *   bytes
unsigned   len
}	decoded

Detailed Description

Header caching scheme

The HTTP/3 headers are sent on the wire in QPACK-encoded form. To dissect the headers, Wireshark needs to keep the decoded header names and values in memory.

To optimize dissection time, and to conserve memory the HTTP/3 dissector keeps all unique combinations of header-name, header-value in a cache.

The cached values are stored in the "pstr" format: name length (uint32_t) name value length (uint32_t) value HTTP3 header field.

The header field contains two sections:

• encoded points to the location of the encoded field in the original packet TVB.
• decoded points to the formatted header string, which is allocated in a cache map, to conserve memory. The decoded fields are used to create an auxiliary TVB which will be used for dissection of decoded header values.

Member Data Documentation

bytes

const char* _http3_header_field::bytes

Decoded header field bytes.

len

unsigned _http3_header_field::len

Length of the encoded header field.

Length of the decoded header field.

offset

unsigned _http3_header_field::offset

Offset of the encoded header field in the decrypted TVB.

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The documentation for this struct was generated from the following file:

• /builds/wireshark/wireshark/epan/dissectors/packet-http3.c