STRUCT IP6T_SRH1(9)

💅 struct ip6t_srh1(9)

okay so this is a page from the Kernel API Manual and bestie, it's literally all about struct ip6t_srh1 — the SRH match options, revision 1. that's the vibe. let's get into it 🎀

---

✨ NAME ✨

struct ip6t_srh1 — SRH match options (revision 1). that's it, that's the whole name section, she's concise 💅

---

🌸 SYNOPSIS 🌸

here's the struct in all her glory — copy it exactly, don't be weird about it:

struct ip6t_srh1 {
    __u8 next_hdr;
    __u8 hdr_len;
    __u8 segs_left;
    __u8 last_entry;
    __u16 tag;
    struct in6_addr         psid_addr;
    struct in6_addr         nsid_addr;
    struct in6_addr         lsid_addr;
    struct in6_addr         psid_msk;
    struct in6_addr         nsid_msk;
    struct in6_addr         lsid_msk;
    __u16 mt_flags;
    __u16 mt_invflags;
 };

like, look at her. six struct in6_addr fields in a row. main character energy fr fr 👑

---

🦋 Members 🦋

okay this is the part where we go member by member, no skipping, we respect every single field in this struct:

• next_hdr — the Next header field of SRH 🫶
• hdr_len — the Extension header length field of SRH
• segs_left — the Segments left field of SRH
• last_entry — the Last entry field of SRH
• tag — the Tag field of SRH ✨
• psid_addr — address of the previous SID in the SRH SID list
• nsid_addr — address of the NEXT SID in the SRH SID list (yes, NEXT is shouting, she's excited, let her live)
• lsid_addr — address of the LAST SID in the SRH SID list
• psid_msk — mask of the previous SID in the SRH SID list
• nsid_msk — mask of the next SID in the SRH SID list
• lsid_msk — MAsk of the last SID in the SRH SID list (yes the original capitalisation is MAsk, we are NOT fixing it, that's canon 💀)
• mt_flags — match options
• mt_invflags — invert the sense of match options 🔥

ngl the three *sid_addr / *sid_msk pairs are giving previous / next / last and i'm obsessed — psid, nsid, lsid, one little family 🧚

---

💜 SEE ALSO 💜

go look at these, bestie, they're right there:

• the kernel file ./include/uapi/linux/netfilter_ipv6/ip6t_srh.h
• struct ip6t_srh(9) — the original, the blueprint, the mother 👑

---

and that's the page!! 🌈 thanks for reading my whole essay about a netfilter struct, you're a real one 🫶

sign-off time: this little number lives under ./include/uapi/linux/netfilter... and it's dated October 2026, page name struct ip6t_srh1(9) — mwah, slay, periodt 💖✨