Date: Thu, 19 Oct 2023 09:14:39 -0700 From: Gleb Smirnoff <glebius@freebsd.org> To: Kristof Provost <kp@freebsd.org>, Igor Ostapenko <pm@igoro.pro> Cc: src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org Subject: Re: git: fabf705f4b5a - main - pf: fix pf divert-to loop Message-ID: <ZTFV74-C4amIm0ru@FreeBSD.org> In-Reply-To: <202310191237.39JCbdXp094554@gitrepo.freebsd.org> References: <202310191237.39JCbdXp094554@gitrepo.freebsd.org>
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On Thu, Oct 19, 2023 at 12:37:39PM +0000, Kristof Provost wrote:
K> +++ b/sys/netinet/ip_var.h
...
K> +/* pf specific mtag for divert(4) support */
K> +enum { PF_DIVERT_MTAG_DIR_IN=1, PF_DIVERT_MTAG_DIR_OUT=2 };
K> +struct pf_divert_mtag {
K> + uint16_t idir; // initial pkt direction
K> + uint16_t ndir; // a) divert(4) port upon initial diversion
K> + // b) new direction upon pkt re-enter
K> +};
This can be written as:
typedef enum {
PF_DIVERT_MTAG_DIR_IN = 1,
PF_DIVERT_MTAG_DIR_OUT = 2,
} pf_mtag_dir;
struct pf_divert_mtag {
pf_mtag_dir idir; /* Initial packet direction. */
union {
pf_mtag_dir ndir; /* New direction after re-enter. */
uint16_t port; /* Initial divert(4) port. */
};
};
The benefit is that in the debugger you will see PF_DIVERT_MTAG_DIR_IN instead
of 1 when looking at a structure. And compilation time failure if anybody sets
it to a wrong value. Using "port" instead of "ndir" when assigning a port
improves readability of code.
This will grow structure from 4 bytes to 8, as enum is always an int. However,
uma allocator backing m_tag_alloc() will allocate same amount of memory.
Sorry for not messaing that in the phabricator.
--
Gleb Smirnoff
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