Issue #2212 Enhances validation of HTTP header names

[carryel]

This is a PR for Issue #2212.

The patch contains two contents.

1. If the HTTP header name contains \r\n and it is an incomplete packet, ignore it and proceed with parsing. At this time, I was wondering whether to allow not only \r\n but also single \n, so for now, I decided to allow only \r\n.
2. Since there is an existing validation utility that validates cookie headers(https://github.com/eclipse-ee4j/grizzly/blob/master/modules/http/src/main/java/org/glassfish/grizzly/http/util/CookieHeaderParser.java), I tried using the existing validation instead of creating a new one.

Overall, I patched it so that there would be no major changes while maintaining the existing logic, and added related test cases.

[breakponchito]

@carryel Do you know if the validation should need to be applied to the heder value also? I tested to include the invalid characters on the value side and those are processed, example:

• curl -i -v -H "X-MyHeader: \nhello" myendpoint
• curl -i -v -H "X-MyHeader: \rhello" myendpoint
• curl -i -v -H "X-MyHeader: \0hello" myendpoint

cases that currently are prevented:

• curl -i -v -H "X-MyHeader\n: hello" myendpoint
• curl -i -v -H "X-MyHeader\r: hello" myendpoint
• curl -i -v -H "X-MyHeader\0: hello" myendpoint
• curl -i -v -H "X-MyHeader\x00: hello" myendpoint
• curl -i -v -H "X-MyHeader\x0A: hello" myendpoint
• curl -i -v -H "X-MyHeader\x0D: hello" myendpoint

in all cases adding the header with a value containing the invalid chars the request is processed

[carryel]

@breakponchito As you know, the validation of header name and header value are different. The header value should be slightly less strict than the header name.

It is true that the header name requires token validation, and the header value requires field-content-related validation.

However, I only did the minimum patch because I was worried about backward compatibility and possible side effects.

There are so many related RFCs that there are slight differences, but if I extract a few, it is roughly as follows.

field-name = token

field-value = *field-content
field-content = field-vchar
[ 1*( SP / HTAB / field-vchar ) field-vchar ]
field-vchar = VCHAR / obs-text