tcp: style changes

[rscheff]

Summary

Break-out of the (mostly) pure style changes from D43470.

Non-style changes include the use of SEQ_SUB instead of
a plain subtraction, for an implict type conversion.

Using curly brackets in more or less deeply stacked if
statements throughout.

Split "} else if () {" with a newline to improve readabiliy:

} else
if () {

Evaluation order change in if condition and preventing
a theoretical overflow.

Use of the ? operator to enhance readability (clearing
of the FIN flag).

None of the above change the function.

[tuexen]

Please keep else if () in one line.

[imp]

Split "} else if () {" with a newline to improve readabiliy

That's not an improvement. Nor is it consistent with style(9). Please don't do that.

[rscheff]

• undo splitting of } else if () {

[cc]

sys/netinet/tcp_input.c

1885

Add another level of alignment because SEQ_SUB is inside SEQ_GEQ. Like this:

SEQ_GEQ
    SEQ_SUB

sys/netinet/tcp_output.c

608

I am in favor of keeping this pair of "{}".

[rscheff]

• address cc's comment

[rscheff]

sys/netinet/tcp_input.c

1885

I'll indent it by a single additional space only, to be visually different from the statment in the if-clause. I have another change with a deep logcial stack of AND/ORed checks, which would end up way too far to the right if a half-tab (4 spaces) were used per bracket-level.

[glebius]

sys/netinet/tcp_input.c

1885

Just observation: this isn't a stylistic change. However it seems safe since both predicates of OR dereference tp.

[rscheff]

• make both conditional calls to tcp_output look similar

[rscheff]

sys/netinet/tcp_input.c

1885

Indeed; on closer examination, I should do a "sbavail() > SEQ_SUB(,), as the former is a uint, and the latter a int, which can not become larger than 2^30-2^14.